I do not recommend doing it.
I used to do it, especially, with the dryer (if the generator is running and you have some laundry to dry, what is the harm, right?)
Well.. the first time the belt slipped off. Took 1 hour to take the dryer out of the compartment, 10 minutes to slip the belt back on.
I blamed it on the bumpy roads and swore I would never do it again..
Fast forward a few years..
Second time the belt broke! Again, 1 hour for dryer removal, plus had to overnight a new belt because these items are not exactly in stock everywhere. So cost me about $150.
I noticed the new belt was a little wider (and fit fine on the motor), so maybe this was a common problem.
I do not think this is a good idea.