hole filling

Have started looking for and filling holes where mice can get into our new 3410. Didn't know there would be so many. The main problems are locating and in many cases not being able to get to where you need to be to fill the openings. The holes around the water lines under the sinks are huge can't understand why they put in a 5in. hole for two 1/2 in. waterlines? The heat vent in the kitchen has had plastic and insulation on the floor around it 3 mornings when we get up thinking we may have a mouse in the hose leading to that vent but can't figure out how to get to it unless I take the bottom covering off and not sure that would work? Any suggestions on solving these problems would be appreciated. (The wife is mouse-a-fobic) Thanks

We had a Raptor with the mice getting in all the time. Killed 8 in one night. Tried filling all holes I could see with spray foam. They still came in and I eventually ripped the bottom off only to find a 2'X2' hole under the shower for the drain. Also found some others as well and I took more insulation and tar paper filled all holes and then call a company to spray foam the entire trailer. They put 2-1/2" of foam (an additional R15 value) and never saw a mouse again. The wife just cringes when she sees one. Will probably be doing the same thing to the Cyclone when we pick it up and warms up a bit here