Being from Maine originally we have always used the Maine Mouse-ah. Check out the link to the description page. http://www.mouse-ah.com/description.htm
It doesn't take care of ants but it will take care of your mice. Another tip is to use the pedetor pray instinct. If you pick up some fox or bobcat urine form any hunting supplier and sprinkle a bit on the ground around the outside of the trailer they will be less inclined to hang around.
The third tip I picked up from my dad who puts his Ford Model A for the winter each year. He buys the big jar of whole cloves and makes saches with them. The smell a whole lot better than mothballs and appear to do just as good of a job. He has not had a single mouse in the car despite seeing evidence that they have been in the garage.
Now if I could just figure out a way to keep the little buggers out of the cooling chambers of my lawnmower and garden tractor. About three times a year I have to get the wrenches out and take all of the housings off the engine and clean out the residents. My dogs have now figured out what happens and come running when I start the tractor up hoping to catch one of the mice making a run for it.