Ants

Could they be coming in on the power cord? Mine was basically a joke as there was also a large hole where the cord came out of the storage box under the couch. I cut a sponge to fit around the cord and push it into the plastic box. Also spray foamed every opening and have not had anything inside for months. My wife can spot a paint drip at 100 yards so she would know.

At home I use borax it's a white powder that you put on the ground I bought mine at Lowes it was very inexpensive to purchase.

Using bait is a good idea if they are in your RV. Keep in mind that the bait is designed to attract the pest.
I do not store any food in the RV, when the RV is set up I spray anything that comes into contact with the ground (hose, power cord, jacks and tires), do not let tree limbs contact the RV.
I have a reminder set on my phone for the first of every month. I check and run everything and look for evidence that ants, mice or other pest are moving in.

Try these http://www.amazon.com/TERRO-PreFilled-Liquid-Killer-Baits/dp/B000HJBKMQ/ref=wl_it_dp_o_pd_nS_nC?ie=UTF8&colid=1A5PLMYX5H6PV&coliid=I2N4VHA4ARRIJ7

Put a mixture of half sugar and half boric acid in a shallow plate. Mix just enough water to make a thick solution. Boric acid is available at any drug store and is used to wash out your eyes. The ants are attracted to it, will eat it, take some back to their nest, and quickly die.