Costa Rica: Chirripo is nice, but is difficult to find the permits. Other volcanoes as Arenas is nice too, but normally is not permit to climb it or when is permit there is huge quantities of turist.
I recomended to you:
Nicaragua: Volcan Concepción and Maderas are really awesome. There is other nice volcanoes easier as Cerro Negro and Telica.
If you are traveling on these areas, I recomended to you to climb Baru, in Panamá better the way from Cerro Punta... great place, you can see both oceans (Pacific, Atlantic) at once from the summit.
or better to go to Guatemala, there are lots of huge volcanoes, many actives, some technicals aswell. Acatenango (top 10), Tajumulco, Santiaguito, Cerro Quemado are very nice options.
non-technical but good physical condition necesary.