If you have an extra lower cabinet, you could put the trash can inside. Problem is, very few campers have an "extra" lower cabinet!
My dog use to dig Kleenex out of the bathroom trash can & eat it. Kind of nice, actually: his poop came out gift-wrapped!
He's also been known to dig things out of the kitchen trash can. I tried a kitchen can that had a lid with a "swivel" door on it. He's just push it open with his nose! Ended up getting cans with lids & foot levers to open the lid. He hasn't (yet) figured out how to step on the foot lever to open the lid.