I climbed "La Gran Piedra" on a modified Russian bike, with just a piece of bread and butter on my stomach when I was around 14-15 years old. Biked around 10-11 km on the road to "Siboney" beach, took the left up to "La Gran Piedra" (called "Encrucijada"). It wasn't a big deal. Anyone well fit, with some biking experience can tackle it.

Yes, the road is full of holes, could get slippery --specially during rainy season. The stiffer areas are similar to *some* patches on the way up to Mt. Diablo, CA.