1. The Sulphur Skyline trail is nine kilometres long, with 720 metres of elevation gain.This is a strenuous hike. I would allow 3 to 4 hours for the hike. I haven't yet done this hike this year, but according to the trail report ( https://www.pc.gc.ca/apps/tcond/cond_e.asp… ), it's in good condition - mainly bare and dry. The lower part of the trail in the forest is wide and easy footing, the upper part of the trail above treeline is very rocky. Regular runners/sneakers/joggers would be just fine, but hiking shoes or boots would be better. (But no point in running out and buying them now ... they need to be well-broken in.)

If you have not done other hikes yet this summer, and if you do not do leg exercises at the gym (i.e. squats, lunges), the downhill portion of this hike will likely make you VERY sore for the next couple of days afterwards. You may also have tight calf muscles from the uphill hike.

2. If you do not have a reservation on the shuttle bus to Lake O'Hara already, unless you are willing to walk the fire road in and out for a total of 22 km (approx. 7 hours), you won't be visiting the lake.

Wapta Falls is a short hike - I did it the other day. I'd allow about an hour to an hour and a half for it. How long you spend at Emerald Lake depends on whether you plan to hike there, or just look at the lake. You don't say where you are driving from; there will be driving time to the Wapta Falls trailhead (this is the point furthest west of the Yoho NP sites you've listed), and Emerald Lake and Tak Falls are up separate roads. (The Yoho Valley Road to Tak Falls is not yet open all the way to the falls, but should be, by the time you come.)

I would plan for most of a day for Yoho NP.

3. Parking is free in the national parks. Lake Louise, Moraine Lake, and Johnston Canyon are the three spots in Banff National Park where the parking lot size does not accommodate the demand for parking at busy times in the day. You can check on parking availability at www.pc.gc.ca/banffnow The usual recommendation for the two lakes is to arrive early - before 8 am - or later in the day (after 6 pm). When the lake parking lots are full, access up the road is closed, and you have to take a shuttle (to Lake Louise). There is no shuttle to Moraine Lake until September, although there is a daily hop-on-hop-off bus service that can take you there.

Emerald Lake in Yoho NP also has parking woes during peak times, but similarly to Johnston Canyon, the parking overflows onto the access road, increasing the distance you'll need to walk to see the lake or canyon. When I was at Emerald Lake last August, we parked about 1/2 kilometre down the road.

4. The Lake O'hara shuttle bus requires a reservation - but the entire summer's quota sold out within a couple of hours of the online reservation system opening, back in April. So unless you want to show up early at the parking lot, hoping for a cancellation, the only other way to access the lake is to hike in and out, as I mentioned earlier.

The Cavell day-use area is closed, until sometime in August.