I can think of many ways to "improve" the security of most storage compartments. Unfortunately most of them will only keep the honest at bay. The simplest thing is to change the cam locks with something other than a CH751 key. While doing this you could look at reinforcing the area where the cam lock engages. I could see adding a section of steel L channel screwed to the existing thin compartment door strip where the cam lock engages and then also screwing it to the floor of the compartment. This would probably require a longer cam lock, but those are available. This would give you a slightly more secure compartment.
However, as you mention, the doors aren't that thick. If they want in, the could simply bash the door in. You could reinforce the door with plywood backing, but this would require visible bolt heads to be effective.
I would be looking long and hard at the storage yards security practices and consider whether better storage might be the answer. Yes, it could happen in a campground or parked somewhere on a trip, but most never have problems with other campers around.
2018 Forrest River Salem Hemisphere 282RK - 2017 RAM 1500 TV
Previous RVs and TOADS
2004 Fleetwood Bounder 32W on WH W20
2000 Four Winds 5000 21RB
1986 27' Allegro
TOADS
2005 Ford Ranger XLT 2WD
2004 Suzuki Aerio
1988 Chevrolet Sprint