The one scavenger tour where you go into the houses and grab items is pretty fun. When playing over wifi with people we made a plan to just grab all the items from each house and dump then by Tortimer. Then each player could search for the items they needed in the shortest time.
The scavenger hunt one is great because it gives a lot of medals. I did the Official Scavenger Hunt Tour and got 13 medals and it only look about 3-4 minutes. ^_^ Easy way to make A LOT of medals.
A tip:
If you're really low on bells, and don't wanna catch bugs or whatever. Then just play a random tour, and collect every single fruit at the tour, and put it in piles of 9, until you max out. Obviously you won't win the tour, but you will win loads of bells when you sell the fruit at Re-Tail.