There are plenty of hose end sprayer products available at any garden center that can be used to create a barrier around your unit. Some last for months. Also plenty of pre-mixed home use sprays that are safe for animals once they dry.
Spray under the unit, spray the unit, spray everywhere. I'd take every thing out of the outside storage areas, and spray or fog every square inch of all of them, do the same for every nook and cranny in your unit. It may take several times to get rid of them, even if you call a pro, don't expect them to be gone with a single application.
