We use our fifth wheel year round. Even when home we still use it full time in our drive-way. AC or heat is on all the time. With this camper, it's now been 7 years and no issues letting things run for longevity reasons.
The difference between the way we use our camper and the way you plan on using yours is if you physically distance yourself from the camper for lengths of time. Ours is always in our possession, unless it's being repaired in the shop for some reason.
The thing you have to ask yourself is, how comfortable are you leaving "things" running if you are not actually "there". What happens if there is a power surge or a power outage. If a power surge occurs, it could damage systems in the camper. And if a power outage occurs, will all the systems in your camper turn themselves back on by themselves, or will they remain "off." What happens if there is a power outage for several hours? How long will the food in your refrigerator stay "safe"? If there is a power outage and the outside temp is 100 degrees, the inside of the camper can easily raise to 120 with no AC and everything closed up. How long will it take for the heat to penetrate the refrigerator and begin spoiling anything stored in there .... not long.
The best answer I can give you is ... running the AC (or the furnace) indefinitely for long-long periods of time does not hurt anything. And actually, will keep the camper just fine.
The problem is, what if extreme weather causes extreme conditions? How often do you return to the camper to check up on it. Five days without power will result in food spoiled in the refrigerator in 100 degree ambient temperature. Bread in a cabinet probably will mold. And canned vegetables could explode under excessive pressure caused by long time excessive heat. (it's possible).
In the end, it all boils down to how often you return to the camper would result in best practices.
Last Fall we were camped at a State Historic Site in Louisiana (I'm a tour guide there). My wife had an upcoming surgery and we left the camper in Louisiana and drove home to Indiana. The entire process took 3 weeks. Before leaving the camper, we ensured all perishable food was consumed from the refrigerator. Granted, there were other things there. But if anything was lost, it didn't matter. Ketchup and Mustard, Jelley's and Jams are all replaceable if they go bad. We set the AC on high. Pulled in all the slides, turned off the water pump, drained all the tanks, and make sure we were not connected to shore water with the garden hose. All lights were turned off. Everything locked up. And we were gone for 3 weeks. Everything worked out just fine. We had no power losses. If we would have, some of the electronics in the camper would have been flashing. Would I do it again that way if we had to be gone 3 weeks.... absolutely.
One thing I STRONGLY advise to to get an EMS (Energy Management System) ... either a portable one or a fixed one inside the camper, and keep it plugged in. Progressive EMS or Hughes Autofamers are the 2 most popular. A "surge" protector is NOT enough .... you need an EMS.... Keep that plugged in. Then the only worry is long term power outages.
