I found that the roads varied from surprisingly good to laughably bad (especially in the mountains).
If you want to go exploring, having a 4WD vehicle with a winch is not a bad idea. The first time I went, I was on a tour bus winding around steep mountain passes with what looked like about 6 inches to spare and no guardrail. One rediscovers prayer at such moments.
Oh definitely. In San Jose and subs, roads were passable. The “new” main route east had suffered a massive landslide about a week before we got there, so we had to snake through a more southern mountain route. All of the semis from Limon coming to San Jose were also trying to traverse the same route. We sat for hours and hours on end. I would put the vehicle in park, lay back my seat, and sleep. Kids would wake me up, and I would move forward, about the distance of a car length, and start over.
I was tickled by the ingenuity of the locals. They would walk to the next little grocery store, buy goods, and walk back, selling them to the tourists caught in the traffic jam.