We did a cross-country trip with Nitschke when he was about 8 months old. he LOVED it! We did a web search for pet friendly hotels and stayed in various cites... Champange, St. Louis, Oklahoma City, Sante Fe, Sedona... all the places we stayed either had no additional charge or about $25.00 and the pup had to be crated if we were not in the room.
We had a Ford Explorer at the time and it worked out well for us.
Oh, we did this in the middle of May and the weather was perfect except for St. Louis... it was brutal HOT