In your owners manual, it should give you a good list of things to check and all places that use caulking.
If you don't have a manual, you can email Jayco with your VIN and they will email you one in about 20 minutes.
I would ad:
Get under and inspect the frame. Coat any rust with rust stopper and then final coat with truck bed liner
Check gease in wheel bearings, address any rust on hubs etc.
Check A/C mount bolts from the inside. Remove 4 screws holding cover to get to them. A lot of people find these loose.
Check the tongue area for any rust, treat and paint. Looks all nice and shiney again :-)
If you add caulking over old, use a paint brush and work the new into the cracks etc. Lot's of Youtube Video's on roof maintenace, electric brakes and wheel bearings.
I took all wheels off (steel) applied rust stop to back sides, and primered for protection. They develop rust.
I addressed outside of wheels as well, primered, painted white they look like new.
Check your tires. Tires are usually replaced on age versus tread wear. 5-7 years. There's a 4 digit code molded into the tire for month/year I believe. After DOT symbol.
Rust stop, paint and grease the screws for any stabalizers.
Check which roof material you have. Probably rubber, so you'll need to use a butyl caulk.
In your manual, you'll also find a list of about 50 common spare parts and their part numbers, where to purchase. Print it off and keep it handy.