If I still had the house - I'd consider a trade of my house for the summer and your 5er in Montana for the summer.
Our Good Sam group camps within 25 miles of Hallsville twice a year - in January and March.
We don't camp anywhere in Texas in July and August.
Most of us are in Colorado, or anywhere place up north.
I even gave up taking the grandkids to Lake O' the Pines, 21 driving miles north of Hallsville, in the summer a few years ago. The heat was always an issue. Now the multi-year drought, the restrictions on no campfires, the low lake levels - east Texas is not longer a place to camp unless forced in the summer.
Apartment is the way to go.
Then come back and visit us when the snow is 40 feet deep in Montana.