Continue camping or pet friendly hotels

I'd look up the hotels in the area's that you want to go to and see if any are pet friendly. There are a few chains that don't charge extra and a few that do. I have never seen one that will let you leave a animal unattended and some also have restrictions as to how many pet you can bring or the sizes/breeds. I've done several cross country moves (military) with pets and stayed at hotels frequently (LaQuinta's mostly) and didn't have any problems, but I wasn't sight seeing, and if the hotel chain offered breakfast we would eat in shifts or have to put the dog in the car (weather permitting of course, hot weather is a no no). We have also used a kennel before when we did want to sight see for a day.

Personally I hope you can find more time or friends to RV with to help justify your purchase, but know that can be tricky.