Don’t be scared it isn’t the Wild West, just be organised.
Lots of apps for stop over places, we used Camperstop, CaraMaps, Parkings. Had the Aires book too but we preferred a regulated site for the facilities. It’s a matter of choice. We also had an HGV satnav, it still took us on some interesting roads but if a bus can get through......
Take a saw, you may need to modify some vegetation (or wooden bollards) to get through if stuck (don’t ask).
We drove until about 4pm most days we were on the move but started looking for suitable overnight stops from 2pm onwards, trying to anticipate how far we could get in the next 2 hours. If we couldn’t find something that appealed on one app, we switched. They are all different and some sites only appear on some apps. We also had a good old fashioned map, can’t trust that you will always get a good enough signal for tinternet. And a camp site book just in case. We are risk adverse!
It is worth phoning or emailing ahead if going to a particular site, just to make sure they can accommodate a big beast. We did find some areas had less choice in sites and so a bit of planning was a good thing, saves having to pull over just anywhere (although I know some prefer this).
Most of all, enjoy. It was the best holiday ever and we ended up in the Algarve (that was our plan, we didn’t get lost).