Here is the real deal on the road conditions in the central and south Pacific regions of Costa Rica.I just drove this stretch of highway last week. 

From Jaco south to Puerto Jimenez on the coastal highway

Jaco to Parrita: paved road in pretty good shape. The bridge in Parrita is almost finished, but as of October 2009 it is still one lane and causes backups. 

Parrita - Quepos: paved road - pretty bumpy

Quepos - Dominical: brand new paved road and bridges in perfect shape. No lines painted yet. There is about 8 kilometers of unpaved road and about half of this is flat and in good shape. The other is typical gravel road with bumps and rocks and there is a detour around one remaining new section. 

Dominical - Palmar Norte: paved road in good to excellent shape

Palmar - Chacarita: HORRIBLE! pot holes in the paved road. A recipe for a flat tire!

Chacarita - Rincon: mostly paved in moderate condition

Rincon to Puerto Jimenez: they are working on paving this and while none of the bridges are complete, the road is paved or well groomed for most of the way to Puerto Jimenez.