Yes, we did. We rent a car ( compact 4x4 - $63 a day inc insurance ) and did a small loop in the northwestern of San Jose. We went to Santa Elena ( 90 miles from San Jose ) which is a good starting point of the Forest Tours ( canopy tours, bridge walks, etc ). We did the Bridge Walk ($20), a 3 kilometres walk through rain forest on the ground and on 8 hanging bridges above-and-through the forest. Stayed at a cosy lodge in Santa Elena - $145 a night, no breakfast, no TV, no fridge !.
From Santa Elena, we drove clockwise around lake Arenal to the active Arenal Volcano. Stayed at
www.hotellindavista.com ( a junior suite room $100 with breakfast ). Our room is on the hill overlooking the lake and the volcano. Beautiful view. It was very cloudy and we couldn't see any mini explosions and volcanic activities that the Arenal Volcano produce daily. We were told on the night with clear sky, you can see red explosions.
The distance between each city is not far ( some 80 - 90 miles ) but it takes ages to get there, becasue most roads are unpaved, very bumpy. The ones that are paved have lots of potholes.