We travel with the latest Trailer Life Campground Directory. It gives us where RV parks are or way out Forest service campgrounds. Check out their website for info on the directory. Also other campground directories are out here so do the google for others.
Also smart phones and google maps are a great source for out of the way campgrounds or stop areas.
The hubby knows a heck of a lot more than we do about RV's in truck stops. Listen to him on that subject.
Campground reservations ??
The wife and I have camped around the country since our first truck camper in the late '60s and have never made one. Now if you want one in a crowded area like Yellowstone then it may be a good idea. But like you say it put you on a schedule. I'm retired also and as a former LTL O/O I don't like schedules....I'm sure your trucker hubby doesn't either.