I know pictures don't show everything and can be very deceptive, but based on your photos, that camper don't look too bad! As old as it is, I think I'd just give it a good cleaning, make sure everything works, and start using it. Replace or fix only what doesn't work.
Some soap and water on the walls and cabinets might make them look a lot better. A bit of Old English, or some polish might make a big difference too. Old and bad carpet ... always a good idea to change out. Still, don't make it harder or more costly than you need to.
Enjoy the camper! But most of all ... have fun! Even with your renovations!
