Location matters. In the 90s here in central FL, incredibly humid, raining most days.
Humidity will destroy the inside of a camper. Mold will grow.
I keep the vents shut, and one A/C unit set to 78F. It cycles throughout the day, and very little at night.
Our fridge is a residential unit. I start it up about a week before a trip, and often leave it running for a week afterwards. If we have any tropical storms/hurricanes threatening, I'll go ahead and start it, just in case.
The smart battery charger keeps my 4 house batteries, and 1 chassis battery, happy and healthy. No overcharging, no self discharging.
FWIW, our travel trailer was purchased new in 2006. I kept the A/C running in it also. We are in the process of selling it to our niece. The inside of the camper looks almost new, while the outside has some sun damage.