Stealth,
I'd recommend (if you want guaranteed security) the motel chain Formule1...
http://www.hotelformule1.com/formule1/index.html ... they are a cheap-as-chips hotel chain, a bit like the "Mcdonalds" of the hotel world but they are clean, well kept, cheap as chips and above all the gates are locked all night so NOBODY can get in. We even ordered pizza one night at 10pm and had to go to the gates with security to take delivery and pay.
There's loads of them about and they can be used to sort of plan your route. Plentiful in France but not sure about spain/the rest of Yerp.
It's nice not to have any pressure and stop where you like but it might be a better idea to book B&Bs ahead and make sure they have a garage.
Sorry to hear about your disastrous stay in the hotel. Gutted must not even begin to describe your feelings the following morning.
Cheers!