Air conditioner cover worth it?

I had a cover to keep the A/C core clean. Used it a couple of years with minimal results and it was a hassle to install and remove. It may still be hanging in the garage somewhere. :R
I'd say don't bother.

Not only the four legs, but also the sawhorses I support the camper floor with during the winter...

Short of some sort of anti-gravity device, something has to contact the ground to support the camper. If it contacts the ground, the mice can climb it.

I've had the camper for 5 years and so far no mice have infiltrated the interior. The air conditioner is a new addition this summer, and it has nice big holes for the mice to get in without much effort.

I'd concentrate far more at making it hard or impossible for mice to get to the air conditioner in the first place. I'd think the only practical way for mice to get up should be the four legs on the camper unit, and making them mouse-proof or at the least mouse-resistant seems like it ought to be doable.

glad you came back, I forgot to tell you ,buy a bottle of peppermint oil, put drops all over the rv inside , and a box of fresh kab, farmers use this in there equipt to keep critters out.

Well, the shroud has those big cooling slots in it which leave very few places to hide. Mice don't like exposed spaces.

That's why I ask.

a mouse can get threw a hole the size of a dime, it won,t matter.