wouldn't gravel be less work intensive and cheaper? I haven't had to do this project myself, so you may have figured that out already. I just know what most people do use gravel and am wondering why you went with cinder blocks. I definitely can see how they would work, just not sure if they're cheaper than gravel.

Cinderblocks aren't cheaper in the short term, but they are in the long term. Our driveway runs through a floodplain and is very wet, so normal gravel sinks in and disappears after you drive over it once or twice. For the last few years, we've been using rip-rap, which has more longevity and does start to build up a stable base after a few years. But we've also used cinderblocks in the worst spots and it seems to give the best results --- all of the spots we've treated that way have lasted five years with no repairs.

I wouldn't recommend this method to someone with an ordinary driveway because it would be too much time and money for the return, but if you're working on wet ground, I highly recommend it.