Pest control needs to be a multi-pronged effort. First of all, certainly stop entry. Seal doors and cracks as much as you can. Then bait close to any points of entry, and repellant around/in your vehicles/storage. There are now baits that contain some sort of cellulose product that when the rodent consumes it, it coats their stomach, making them feel full, so they stop eating/drinking. Put that near potential points of entry, and along any walls, preferably under stuff to help keep the pets and kids from messing with them.
Note that if they're already 'home' and have started reproducing, when you kill momma and poppa mouse, their kits won't last long, and really stink up the place.
After that, you want to try to keep them from wanting to come in. I've read mixed reviews regarding the 'sonic' devices, although am about to try them myself. I've had fair luck with dryer sheets. The trouble is, you have to keep swapping them out. If you can't smell them, you're close to the point where they won't repel the rodents, either. If you have any vehicles/machinery that doesn't have a catalytic converter, stuff sheets up the tail pipe to keep the little monsters from making a home in the cylinder head, or cylinder. They can, and their urine is very corrosive.
I've also had problems with the critters creating nests in the hood liner, so now leave the hoods up for the long-term storage vehicles. I've had chewed, or ruined hoodliners in three different vehicles. They LOVE to nest there.
Good luck!