Possible but unwise. What if there is an earthquake, closed roads, landslide, traffic accident, strike etc? Staying in Alajuela the night before wouldn't be so terrible for peace of mind, would it?
Any private transportation will have to be arranged ahead of time. You may be able to find a taxi to do it. However I would suggestyou arrange the transportation through your hotel. Hotels do it all the time and know who in the area is reliable. Or you can check with some of the drivers that have been recommended on the forum and get quotes.
edit - but I agree with Sara that staying near the airport on the last night is not a bad thing.Edited: 16 January 2013, 18:57
Thank you for your responses. I have emailed the hotel about transportation as well. I understand that it would be wiser to stay in San Jose overnight but I am not really interested in staying there. I suppose that I could leave La Fortuna late the evening before so I don't have to do anything but sleep there and go to the airport.
Just be sure you see the vehicle first...that is in great conditon...good tires...etc...
What benefit you may have from sleeping half a night in a hotel in La Fortuna vs. sleeping full night in a hotel in Alajuela? You can still stay in La Fortuna till 6 pm (when it is dark) and have a private driver to take you on 3 hours drive to Alajuela, coming early enough for a nice dinner and relaxed sleep before your early departure flight. Again, only difference is where and how you will sleep.
Are you aware that the Airport is not in San Jose? The airport is about 30 minutes or so from San Jose.Edited: 16 January 2013, 19:36
Please - do yourself a favor and go to Alajuela, this is where the airport is located, the night before your flight. There is lodging of all sorts and prices less than 20 minutes from the airport.
As you say, you can arrange transportation - or even take the bus - and arrive late afternoon or early evening. Have a nice dinner, take it easy and no need to get up at 2 am to get to the airport or stress about what might happen.
Xelas leaving at 6 pm sounds like a very good idea. My reason for not wanting to stay in San Jose is that my time in La Fortuna is short so I don't want to waste time in SJ but if I leave in the evening I can still enjoy LaFortuna most of the day.
Roadadvisor I will be sure to check the vehicle first so I don't get stranded.
There is a very comfortable hotel in Pavas, just a few minutes from the airport. It's not fancy - I stayed there once - but it is nice and about 5 minutes from the Pavas airport. Isla Verde -- and there's an excellent Chinese restaurant on the ground floor.