Hi batya,
With only 5 or 6 nights, you’ll want to pick just a couple of places to stay. Drive times between some of those destinations are considerable because of mountains and road conditions. You mentioned driving at night, which we don’t recommend. A lot of roads here are not well marked, many don’t have lines painted or reflectors, and it can get foggy, which makes visibility really limited. Of the 4 places on your list, we’d recommend a La Fortuna (for nature, the volcano and hot springs) to Jaco (beach time) loop then back to San Jose airport. If you’re feeling ambitious, you could always visit Manuel Antonio on a day trip from Jaco, because it’s only a couple of hours away. Hope that helps. Good luck with the rest of your planning!