what do dogs usually like?
Spoiler
A bone maybe? Pick up the dino-bone at Archie's and give it to the dog.
how to get the key out of the well:
Spoiler
Take the rod from the hermit's backyard and go to the airplane. Open the hatch on the airplane and start the engine by pushing the green button. Use the rod with the coil and it'll become magnetized. Go to the well and tie the rod to the end of the rope, then lower the rope and pull it up again. Now the key is attached to the rod. Take it.
Good luck!