So we spent one night at the Hakone Prince, and my feelings about it are mixed, like the reviews. I feel like your happiness here is dependent on how long you are staying and why you are in the area--and how much you want to spend. We got a good deal on a room so I decided to go for it--about $180 for a hotel that seemed to be a high-quality resort hotel, and I've paid more than that for those. Figured we'd leave Tokyo in the morning on the Hakone Free Pass ticket, do the circuit up to the hotel, then finish the rest the next day. I'll discuss the Hakone circuit later in this review so you don't have to read it if you only care about the hotel, but the main thing to know is not always made clear by other reviews/guides: you CANNOT get to the hotel on the pass. You MUST either pay extra for a boat, find and pay extra for a bus, or reserve a spot on the hotel's free shuttle from the station. We were a little worried about this so after we made the reservation, we emailed the hotel to ask for a ride on the free shuttle, but they never responded so we ended up on our own. I think if you ask for it when you reserve the room you should be okay, but since we didn't, all I can tell you is they didn't reconfirm via email afterwards. There were only three times you could get a shuttle, too, so if those times aren't convenient, you're stuck.
So really do think of the circuit and the hotel as totally separate. Some guides hint at this, but know it's absolutely the case.
Also people aren't kidding about the closing early and opening late business, but let me clarify a little from what I experienced vs. what other reviewers were saying. Between 4pm and 10am there is NOTHING TO DO and NOWHERE ELSE TO EAT if you don't choose to eat at the main (and quite expensive) hotel restaurant. The boats aren't running, the ropeway isn't running, the shops are closed, the cafés are closed, and you are in a resort that is basically separate from all the other towns so that's it. Hilariously, there are multiple signs advertising a bar in the hotel with drink specials--but the bar was never open. We looked more closely at the signs and they seemed to be saying the bar (which is also the breakfast cafe within the lobby) would start having these drinks at night in September. It being June, we wondered why the big posters everywhere offering and then removing an option we really wanted. Oh well.
The onsen is not divided by gender; the dressing rooms are, but the onsen is shared space and you are not allowed to wear a towel in the bath, so you can't cover your bits. I like onsens but I prefer the single-gender onsens or the ones where you can use a little towel if someone's staring inappropriately, and here you're out for all to see, so be ready for that. The onsen is the thing to do between 4pm and 10am. So if you are here to enjoy the onsen, it's a GREAT choice. If not, or if you don't want to spend hours there, you might want to think about it.
The view from the walkway in front of the property is GORGEOUS. You are right on the lake and it's a very peaceful, lovely space. The property is arranged to block out everything else, and you're not around anything anyway, so if you sit on the one bench on that path and look at the lake, it's heavenly. This was my favorite thing. Unfortunately, they didn't have more seating and the grounds were being worked on while we were there so they didn't allow you to walk on them and that little strip of paved walk and bench were it for the view. Our room faced the building, so if you got a room facing that view, liked a mixed-gender onsen, and were generally a chill person, you might really like this hotel. The rooms were huge by even American standards, beautifully appointed, and cozy. Each has a balcony, although sitting on ours would have meant being looked at by people walking through the hotel lobby, so we didn't do that. Make sure your room number is not in the 20s, because these rooms face the building. Get a third-floor room if you can--we'd have faced trees rather than lobby had we gotten a room directly above ours. But I suspect you'd have to pay more--the place was largely empty when we went but they said this was it for rooms for us. Not sure if that was the "gaijin special" (put you where no one else can see you, which happens in Japan) or just because we got a good price on the room and they wanted to save the nicer views for later arrivals (who would have to come in a car, and let's be honest weren't coming). Still, I have to say the room was fantastic, and the view from the path was also great.
It's also just a deeply weird joint; adjoining it is a little "boardwalk"-style area with a petting zoo, goose-shaped paddle boats, and places to eat. All were closed the whole time we were there (from 5pm to 11am) except one cafe that opened at 10. The gondola up to the mountaintop next door opened at 9:10, and this was a great (short and kind of expensive for the trip) ride and view from the top. So if you wander the grounds after 5pm, you are mostly alone at a closed-down boardwalk with limited views. But it could be fun if you were there for a couple of days with kids and liked kitschy stuff like that. Then again, though, the mellow-nice room-good view from your balcony-fancy restaurant-onsen part is not very kid-friendly. So it's like two totally different audiences would be half happy. Weird. The main hotel is definitely not the place for kids.
There's golf; we don't golf. That might change everything, as would having a car. I think if we'd had a car and two days and liked to golf and eat at the same restaurants for every meal, it would be a dreamy, near-perfect experience.
The Hakone Free Pass thing is also kind of strange. They make it sound like a sort of Tweetsie Railroad experience but the train from Hakone Yumoto up to the cable car is really just a very old, incredibly slow commuter train FULL of people, mostly older (60s plus) or younger (under 15). There is no view from either the small train or the cable car. The ropeway is AMAZING--a big gondola across a bunch of mountains to the lake. Only it was raining/cloudy when we went so we couldn't see a foot past the window. Only worth it on a clear day, but totally worth it then. The boats--well, we didn't take the boats, because we only left Tokyo around 11am, and this meant that by the time we got to the boats they were done for the day and we were stuck in the town where the ropeway ends (Togendai). All we did was take train to train to train to cable car to ropeway, stopping for less than an hour for lunch at the Gyoza Center (awesome) and an hour at the Open Air Museum (also awesome). It wasn't until we got to Hakone Yamoto that we got a "real" itinerary that showed that the whole thing stops around 5pm, and we just made it to the boats by then. We were the last people on the gondolas and they ran us down to a shuttle bus because the second half of the gondola trip was being worked on, and then they ran the bus down to Togendai and left us there. Yikes! Luckily my Japanese was good enough to get us to a town a short walk away and we had Pasmo passes for the bus there, which took us straight to the hotel. But no one we met in this stretch spoke English, so if you don't have some skills you could be really stuck. We never saw a cab. So basically we raced through the circuit and still ended up stranded in the middle. If you want to at least get to Moto-Hakone before your time is up, leave Tokyo earlier than 10 and don't wander the towns on the circuit.
Back to the hotel issue, if you are staying at the hotel and don't mind paying, you can take a boat from the hotel dock (starts at 9, was done when we arrived at 5ish the day before) to any of the Free Pass docks and catch up with the circuit again. We did this the second day and left from there. I think if you want to go to antique stores and the museums, see people, and try different Japanese restaurants, you should not stay at the Prince Hakone. Stay at one of the other towns where the bus service is on the pass and roam to your heart's content. If you want a couple of days of total quiet and you have enough money to eat at the hotel and use the boats or drive a car, then stay there. It's beautiful. But totally disconnected from the rest of the circuit.