If you like historic/ quaint towns, then you might consider the Romantic Route (Romantischestrasse), the Southern end of which is Fussen. I know that's a bit away from where you originally wanted to be, but there are nice places on Lake Constance and you could pick up some of the Romantic Route before heading for Fussen and then over the border into Austria, We love Rothenburg-ob-der-Tauber, very touristy and busy in high season, but well worth the effort to see it. Can particularly recommend the Nightwatchman evening tour. Neuschwanstein castle is near Fussen and also worth a look. As Lutz says, you'll be lucky to find CC sites in July and the best places will be busy but the sites are generally very well run. Site access roads tend to be narrow with tight pitches, so a Motor Mover is a big help. We've managed without up to now, but finally succumbed after some struggles last year!