I can't help you with BLM CGs, but I'd suggest you purchase the Rand McNally Road Atlas from a bookstore, Wal-Mart, etc. National forests (NF) are clearly displayed where you can at least first determine if there is a NF near or along the route you are traveling. If you find one, go to our website at
www.forestcamping.com and select the NF. Research the campgrounds displayed and see if there any meeting your criteria.
We use the Delorme map software programs extensively and have found the Delorme Topo USA software program particularly useful in locating many public campgrounds. So, although a bit pricey, you might consider researching Topo USA on the Delorme website -
www.delorme.com. Be sure to confirm they are still providing public campground locations, which if they do in their latest version, you can also get the GPS coordinates. Using this resource along with our website should be helpful for you . . . Fred