We went with 3 adults and 3 kids on a 19 day package put together by Rod at CostaNica Tours. It included many of the activities you have in mind, including the PureTrek canyoning (not as "kid-friendly" as they advertise, but fine for adults.....it does involve alot of standing-around-time, though, while waiting for other members of the group to descend. And there' no time or suitable place for swimming at the bottom of any of the waterfalls). We went (half-day) rafting on the Sarapiqui with Aguas Bravas, which provided our transport from La Fortuna, (and back there for those who weren't staying overnight close to the river). They were very professional, well-equipped and fun--more so in all respects than companies we've rafted with on rivers in W. Va. At Monteverde we loved the Finca Valverde's lofted cabinas (a short walk to town, but nestled-away), though the front desk staff was woefully ignorant about the short-but-scenic forest trails we discovered, right on the hotel grounds' hillside. We LOVED the ziplining and tarzan swing at Selvatura (from Monteverde), and the guided bridges walk there was also wonderful. We enjoyed the all-day Cano Negro tour. The night tour at Monteverde Reserve was just "OK", without enough visible sights to keep the kids from getting sleepy & winey. We stayed at Hacienda Guachipelin and enjoyed the lovely grounds, a long horseback ride and a waterfall hike & swim there, but the food (other than buffet breakfast) was so-so.
At Arenal, we stayed at Erupciones Inn, on a dairy & horse farm with a great (luckily, clear) view of the volcano, but no food or beverage service (just the included, light breakfast), and an 8 mile taxi ride to town if you can find the owners to call one. There's a great and reasonably-priced steakhouse restaurant, El Novillo, about a 1/3-mile walk down the road, though, so we ate our meals there, with the bonus of its spectacular view of glowing, night-time volcanic action---but we're told that clouds obscure the view 80% of the time.
Allow more time for Tabacon, if you can. We went at night after an afternoon volcano hike, and wish we could have seen the gorgous landscaping and setting during daylight hours....and we could have easily spent a whole day in the various hotspring pools there. The buffet dinner was the best food we had in CR.
We went to Samara Beach instead of Playa Grande since the turtles at Ostional lay eggs in July but the leatherbacks don't visit Playa Grande then. The turtle tour ended up going to another remote beach, south of Samara down some really rough roads toward the Isleta Resort, instead of to Ostional...and the guide was pretty unprofessional, but we did get to see 3 turtles laying eggs. We stayed at Brisas del Pacifico in Samara, one of only a couple of beachfront hotels. A brand-new one down the beach that looked very nice, opened the weekend we left, just in time for a group that arrived to stay there. Brisas was fine, though its restaurant menu was very limited and there were very few restaurants along the beach or in town (open during the 'green' season, at least).
We also went to Drake Bay (Marenco Lodge) for 4 nights, and stayed at Neotropico along the Sarapiqui, adjacent to the Tirimbina Reserve.
For the 6 of us, Rod arranged comfortable private or shared (as with the van-boat-van trip from Monteverde to La Fortuna, across Lago Arenal) transport. Their package included (besides hotels and transportation) most of our tour activities, which we later learned would have been quite expensive to book separately, and we were glad he'd chosen reliable providers for us so we weren't confused by cost comparisons and alternative tour choices during the trip. For some reason Marenco's meals (even breakfast) and tours weren't available within the package, and they were quite pricey, with the isolated location making us captive customers. CostaNica was also the only tour company we checked-out that included transport to & from the Liberia airport in their package (others would have required us to get a taxi for that, and with 6 people a van-taxi is not always available). We stayed at Best Western Las Espuelas our 1st and last nights due to its much-closer proximity to the Liberia airport than Hacienda Guachapelin, which was booked-up our 1st night there anyway.
Rod went out of his way to meet our tour and budget criteria (making requested revisions up till a week or so before our trip), and was very professional and generous with us in accepting "last-minute" credit card payment (from a US-based processor, so no foreign exchange fees on our credit cards). He also refunded a credit to us later for the difference in pricing on a room-type-change (due to construction activity) at Brisas, and hotel change (the original hotel, Selva Verde, he'd put into our package for Sarapiqui was full). He is very interested in feedback and in keeping himself up-to-date about all the options available for different destinations, tours and accomodations. We would recommend Costa Nica highly and wouldn't be surprised if you would save $ (compared to booking all the tour components separately, yourself) through them rather than it costing you more.
