If you find a rest spot and there are minions on the board what happens?
The rules state: If that card is an item, weapon, armor, accessory, scroll or trick, the player may either:


put it into the searching mouse's pack for later use, or 
immediately discard it for 1 cheese.


Since Rest Spot is not any of the types listed, I don't think you can discard it for cheese.  And "Play immediately" is pretty clear about not holding on to it for later.  So I think you just discard it and nothing happens.