Congratulations on you "new" camper
and welcome to this great site!
I too have an older camper that we enjoy greatly, the previous owners took great care of ours for 27 years and and still has plenty of life left.
A few things I would recommend, check all the seals around windows, vents, door and roof and reseal as needed, being older the seals dry out and need some TLC.
Also have your wheel bearings checked and grease repacked unless you know for sure they where done recently.
Find out what brand and model the accessories like A/C, hot water heater, refrig, etc... are and google manuals, read and learn about them.
When you plug you camper in many of your items in the camper do not directly run on the 120 from your plug. the 120 from the plug goes to a converter and converts the 120 to 12v DC to charge a battery and run the lights and some other items.
Learning the camper is as fun as camping IMO.
Again Welcome! and there will be others that chime in with more info as well