I use Microsoft's Streets and Trips - and put in my starting location, my ending location and the places I THINK I want to stop along the way. I say think, because I change things all the time. Then I check distances, etc. I make mental notes of which cities might have a walmart or such if I think I might stay at one. I don't make reservations, because I never know how far I'll actually drive each day (until I'm due someplace
) as I'll stop at the drop of the hat if something is interesting. I've had days I haven't made it more than 20-25 miles. And others that, while the scenery is nice, I simply don't feel a need to stop and drive further. I do make note of good boondocking places (rarely stay at walmarts, stores, etc anymore) and will check those spots out - even for if I might not stop this time, if I like it, will note it for another trip. I also check out Passport America parks along the proposed route - in case I want a night to do laundry, etc.
I plan the route off the highways - and it's easy to do with S&T - but then I always look at my atlas, too ... and when I program my gps, it never wants to go on my proposed route, so often have to reprogram it quite regularly (making my end point sometimes only short distances on the roads I've elected). That's actually nice, cuz I'll program in the places I think I might want to sightsee, etc ...
My routes are often in jello, cuz a road sign might take me to something interesting I didn't know about, etc ... and I just go with the flow.
(I do make reservations on the occasional major holiday (or find a good boondocking spot to hunker down) - depending on where I'm traveling at that time. Also because I don't like to travel on those occasions, too.)