FastGuns / Hallmark - how to provide extra camper security?

Long shank padlocks from the big box stores work just fine.

Or a sign on the side of your TC something like this:
Thieves will be shot and survivors will be shot again.

Or the problem could be when you live....LA....

Up in this neck of the woods we leave our keys in our vehicles and our homes and campers unlocked. Crooks know they may be facing the working end of a weapon if they attempt to steal. Not worth the price, so most leave things that don't belong to them, alone.

Good luck.

Lakeside