CR301 out of Cypress Mill is paved for less than a mile, then is dirt all the way to 281. Wimb., Henley, DS, Blanco area: CR410 (Middle Creek RD) is combo p&d, has a limestone bed creek crossing at the far north end. CR 407 (Chimney Valley Rd) & 408 also combo, CR113 (Red Corrall Ranch Rd) is all dirt. Cr 219 is all dirt. CR 405, 406, & 411 are mostly dirt, I think...
Crabapple Rd southwest of Blanco was mostly dirt. Althaus Davis Rd (CR 310) between 1323 and 962 is dirt. CR 203 is paved, I can't remember 204 & 205. Fisher Store Rd (CR 181) is paved, but fun. CR 213 doesn't go across the Blanco River anymore (private landowner), and is paved.
Caldwell and Bastrop counties are chock full of dirt roads. My fav is Sand Hills Rd (the little dirt dead end part off to the left after the long straight paved part), behind Red Rock.
Get the South Central Texas map from Lone Star BMW or Mapsco- It has all the CRs, unfortunatly doesn't say p or d.