This is the trick I use. o: Not sure if there's any better ones, but.
If you already played as Mayor, it won't work. It has to be on a new day where you haven't played yet.
Click 'New Save File,' go through the boring cutscene with Rover & all that. Go to your campsite, if there's a camper that you like, save your game & just delete that new character's house after.
If you happen to not like your camper, just Power Off and repeat those steps. It's real tedious and time consuming, especially since there aren't always campers in your tent. But, it's useful. This also works if you think a new neighbor's coming in. c: