Sprinkle Comet or Ajax cleanser powder around your tires, steps, jacks and anything else that comes in contact with the ground. Readily available in stores.
Borax mixed with sugar in water kills ants. Ants take it back to their nest and kills them all. But you need to keep the ants out immediately and can't wait for a whole nest to die.
We over-nighted at a CG in Bakersfield that was also an orange grove. At check-in, they told us we needed to spread Comet on the ground because they have lots of ants in the area. Of course, they gladly sold us some Comet. :R Woke up the next day and there was nary a single ant anywhere outside. Not the ant season apparently. When we pulled out of the site, it looked like a CSI crime scene investigation with an outline of white powder on the ground!
My son & I once tented at Laguna Seca race track in Monterey. Woke up and found little fire ants crawling all over the inside of the tent. :E I wish we had known about Comet.