I was a paying guest not the owner or an employee. Back in the Uk now so I cannot tell you the answer.

yes, you can

I think it was $40 each. There is a deal that includes a meal but it was fairly basic food. We paid separately for food. That price is from 10am to4pm. There is another period from 4 to 10pm too for the same money. Lots of places to stay. We stayed at Campo Verde which was very good. We reviewed it too. They recommended reservations but we didn’t and had no problem. You can visit and view the springs area for free to see if you like it. We did that and went back the following day.

We just went on our own schedule, you don’t need to be there exactly at 10. On the other hand, we were and almost had the place to ourselves.

Shouldn’t be a problem. The main roads around there seemed easy to follow and not bumpy/pot holed. The road to Arenal volcano was very rocky so I would avoid that one in the dark. We also did the springs in the evening and enjoyed a meal in the restaurant too. Hope you have a lovely time.

Should be fine. 'Cause of the ambience though, best if they're not the running around loud type.