You can also choose to leave it disconnected. The wire from the house side of the isolator is not that fat, and likely has a fuse at each end. Likely 50a DC circuit breakers. You could pick whichever end that is easier to get at, by the house batts or by the engine batt, and swap that CB for a fuse you can pull.
Chev trucks have the 7-pin always live and nobody dies or anything. If you want to keep the engine battery isolated you just pull the 40a Stud 1 fuse or else pull the 7-pin.
No reason you can't do the same thing with a MH set-up.
