1. Start by making sure that no villagers are moving out. The easiest way to do this is to reject a moveout offer from a villager; once you do, no matter how far you time travel in the future, no other villager will move out.
2. Exit the game and go to your system settings. Set the date two weeks forward.
3. Load your game with your usual mayor. Isabelle will tell you that it's been a long while since she saw you.
4. Since you started from a 'no-moveout' state, all of your villagers will still be in town.
HOWEVER one of them will be scheduled for moveout soon.
This is the important part: Talk to everyone you see roaming in the town. This means every villager walking about outside of their house. This will get their "I haven't seen you in a while!" dialog out of the way.
Why only the villagers outside their houses? Because the moveout villager will be one of them. A villager who is set for a moveout will not stay inside their homes as the game wants them to ping you. Something like that.
5. Save and exit.
6. Reload your game. Walk around your town and wait for one of the villagers to ping you. Almost always, that villager will be the one who wants to move out. If it turns out that they just want you to change a catchphrase or give you a nickname, repeat step 5 and reload the game. Otherwise, depending on whether you want that villager to stay or not, give them the appropriate response.
7. Until the villager you want to move out pings you, keep repeating steps 1-6.
Scenario:
- I want to kick out Stinky. I set the system clock 2 weeks forward after making sure that no villager will be moving out in that time period.
- I talk to everyone in my town to get their "I miss you!" dialogs out of the way. Stinky is one of the people who is walking outside of their homes.
- I reload the game, and carefully walk past every villager I see. Vesta pings me. It turns out she wants to leave the town!
- I say 'no'' to her plans, then save and exit the game.
- I set the system clock 2 weeks forward again. Since I just rejected Vesta, no one else will be moving out and I can safely load my mayor as usual.
- I talk every villager walking outside, again. Then I reload the game and walk around for someone to ping me.
- Stinky pings me! I say my farewells, then save and exit. I then go back to system settings and set back the date to normal.
- I play the game as usual, with the happy knowledge that Stinky will be in boxes.
Some caveats:
* Sometimes no villager will ping. This can either mean that they're sick, or that for some unusual reason the game didn't trigger a moveout. If you're paranoid, you could always play with the system date again -- exit the game, set the system date to one month forward, then start the game with a
new character. If you see a missing house, that means they will be the one moving out soon. Return your system date to normal and load your game with your usual character. You can then prevent that moveout if you wish.
* It's possible that you will travel months and years forward trying to get that one single villager out of your town. If you wish to return to your normal "time", you can set your system date back to your current date and load the game with no issues. Game-wise, this will just be the equivalent of TT'ing 1 day, even if the difference in system dates is weeks and weeks.
* Don't do this method for hours at a time. Make sure to take breaks and always keep a clear mind as you TT willy-nilly. I've lost a villager by being careless; but I've also successfully TT'ed out one single villager in a town full of dreamies so it's certainly possible. Just be careful, as with any other method.