My father and I rented a 4 WD and toured on our own in Feb. Just wanted to share a few things from my trip that might be of interest.
Two less-mentioned places to stay that we really loved: Hotel Campo del Silencio near Arenal was just lovely. A smallish number of wonderful private cabinas with the really friendly owner (a botanist), his wife & their staff doing all they can to make your stay fantastic. Bird perches from the breakfast room and lots of birds throughout the grounds. Good view of the lava while we were there too. Also really enjoyed Posada Andrea Cristina in Puerto Viejo de Sarapiqui. A small number of cabinas, not fancy, but nice rooms with everything you needed & private patios. A great breakfast area with bird perches with birds we didn't see anywhere else. Fantastic for birding & you don't have to walk anywhere to see them. Alex or his son can take you to see some local macaws, too. We also stayed at the bungalows at Selva Verde---very nice in a completely different way. Amazing walk (long, but my 86 y/o dad did it) back to the rooms. Too big of a place for my tastes, but you do feel off by yourself in the bungalows. Spent one more night at the Centro Neotropico (had a very difficult time booking this area, so stayed at all three of these places that are very close together). Lovely, but it definitely had the tourist group feel, and was too well groomed for my taste. We got shuffled off to a remote room without a great view, due to all the groups. I couldn't book the Bat Tour they had for either of two nights for this reason either.
In planning the trip, I had trouble figuring out about the dirt road to Cano Negro. Supposedly it was in its best condition at that time of year. I am very used to driving dirt roads, and let me say this was one of the roughest ones I've been on. It took over an hour to go the 12 miles. The drive from Fortuna to the cutoff and then on to the Nature Lodge was more beautiful than I had expected, however. And we did have a nice private boat tour from a local man for $30. 4 WD was also a great idea for getting to Bosque de Paz Lodge (an amazing place to stay & quetzals were seen there during our stay).
Had a very interesting local dining experience at the "cattle restaurant" in Muelle San Carlos on the way from Cano Negro to Puerto V. You eat upstairs where you can watch the cattle being auctioned on certain days of the week. No tourists except us when we were there. Interesting even without the cattle.

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