They offer pickup from the local hotels in La Fortuna. Not sure from Liberia, seems to be 2 hrs away. I've used interbus to shuttle between towns in costa rica.

It's a lot of activity--especially doing all three together. May be too much for a child of that age, but you can always ask?

You would have to arrange transport to get closer. They may be able to do that for you at the tour company but be warned it’s not cheap. We actually ended up using Uber once when we were there because the transport costs are so pricey. I think if I went back I would’ve bargained more on the transport fees— I feel like we were getting “gringo prices”

It’s priced per person. So you can go by yourself but they will probably put you with another group

Yes, there is a pool that runs off from the fall that you can swim in. The fall itself is too powerful to swim directly underneath, but we were swimming fairly close.

Sorry - not sure what info you are looking for - how many miles we walked during the tour or the total driving distance involved between sights? Mark S provided info, however, I do not recall walking 8.3 miles - perhaps he was on a different tour? More in the range on 4 miles - best guess estimate.