it always takes me 2 days for a camper to move in. apparently it's not such a regular pattern with everyone else. i think it can take up to five days, maybe more.
i once saw chester's plot on the title screen, but after loading my town i couldn't find the plot anywhere. then a week or two later the plot was back for real, in the same spot as it was on the title screen before. i don't know if that has anything to do with how long a villager can take to move in (chester was a random move-in, not a camper). i guess the first time i saw the plot, the game started planning his move-in and it just picked a random day to set his plot down for real? idk, this game is weird when it comes to villagers.