You can buy a decent used Class B van for under $20k.
You can buy a new 1-ton gas engine 4wd truck for about $40k and a decent used camper for under $10k. I purchased my used 8' camper for $6k nine years ago and it's still in great shape and worth about $6k.
You will not want to run a generator all night to run the ac. During the hot summer, get a campsite with power. Alternative is just to run a 12V fan which you can run all night off the battery. Other alternative is to go up in elevation to get cooler nights.
