If your cats are accustomed to being inside, don't let them out. A new location is always scary and the risk of them running away in fear is great.
If a cat is accustomed to being inside and outside, and since yours are declawed, consider a screened tent with floor. The cats can see outside, get lots of air, and be safely zipped inside the tent. You'll have to set it up, carry the cats to the tent, zip 'em inside, then reverse the process, but it's a whole lot safer for them.
Or do the cage off a basement door that has cat access back into the MH cabin. Fresh air, a lounging place to watch from, and safety only a few steps behind.
Our Spotacus thought the MH was a giant box. He loved being inside it and didn't ask to go out much, even though he's an indoor/outdoor cat. On the very rare occasions we took him out, it was on a leash. He didn't like that, but tolerated it to be outside with us.
He doesn't like the trailer much, but doesn't try to go outside, either. He does like riding in the truck with us, though. Strange cat...