How to do google search on camping along a certain highway.

It takes time, but I will use Google maps satellite view to find wide spots on the road, or possible pullout areas. Then use the little man to 'drive' the area and check it out further.

If I find something promising I'll grab its lat/lon, and put that in the Garmin. Be sure to get several as most of them do not work out - with being hilly or steep is the usual reason.

Of course this advice is moot if you're looking for a campground, but since you posted in Public lands, I thought that's what you wanted.