I am jealous. I'd love to have your home, but not your bats!
Bats aren't aggressive and are probably not going to hurt you, but they can carry rabies (though it's not as likely as the old wives tales would have us think) and parasites, like mice, fleas and ticks that can infest your house.
They are protected in many places, so you can't kill them and it sounds like you don't want to anyway, but you can discourage them from coming in. I am sure they are just as unhappy about wandering into your living space as you are about having them there.
Sealing up any cracks, as you have been doing is a good start. You may want to set up bat houses outside on the side of your house or barn, or on the side of your trees and seal up your attic space as well to make sure they are really living separate from you. Make sure all the bats are out first though, (including the babies, who won't be full grown till fall) see below. There are many websites that have plans for making bat houses, but you should also be able to buy them ready made at any nature store.
You can use an exclusion net so the bats can leave but can't return to clear out your attic before you start sealing things up.
For your mudroom, you might try leaving the light on all night. They'll try to find a darker place to settle in.
Those sprays you can buy to keep dogs and cats off of your yard will also keep bats off, about as effectively as they keep dogs and cats off...
Check out http://www.batcon.org… for more info and tips for humanely getting rid of problem bats.
If all else fails, call your local animal control department.
(Rated by 2 Council Members)