Normally if you talk to him/her long enough he/she will ask to play a game of rock paper scissors and if you win he/she will move in but if you loose he/she will ask for one of your items.
That's how I got Lucky to move in from the camper.
I just got Gwen by visiting her campsite with a pyramid in my pocket. She played "charades" with me stating if she won she would get my pyramid, if I won she would move into town. Obviously I won. Hope this helps. Just try carrying something in your pocket when you visit your camper.
Could try ignoring him, but then you have those pings to answer which could mean anything from seeing something they want, pwp suggestions or them wanting to move out. They're really hard to ignore then...
I'd say be mean to them when they want a favour or something, but if you're a kind person, you probably don't want to do that either... So I'm not sure... Time traveling has the danger of losing someone else so I wouldn't suggest doing that.
What I did was make a new villager. Have them talk to the villager once and then ignore them. After a week or so they should ask to move out. Being mean does nothing. This video explains it a bit better!