Okay, I have had mice issues during summer months as well. But over the winter I use real peppermint oil on cotton balls sprinkled throughout the MH. I even put it down below in each of the areas for power/batteries etc. I make sure it is where mice can come in or where they can chomp on wires. I also put out old fashioned mouse traps but usually after about a week, I don't catch any more as the peppermint oil is spread around the MH they seem to not try to come in.
Make sure you use REAL peppermint oil, not the immitatiion oil.
I agree, DCON can cause more issues than it helps. I even use the peppermint oil in my attic at home and I have had no mice for 4 years since I started it. I do find the old fashion mouse traps with peanut butter will catch the few that may be in the MH already.
Good luck and let us know how many critters you find.