I purchased a '71 Winnie 6 months ago. It was in great shape, 60K miles, almost perfect body, and interior, and a very solid engine.
I was considering towing a small trailer for a MC and extra stuff, so I upgraded the engine with a new Edelbrock carb, and intake, electronic ignition with a "ready to run" distributor, a new performance cam, new starter, recored radiator, and a transmission cooler.
On the inside I replaced two vents with fantastic fans, replaced the heavy and huge steel freshwater tanks with a PVC tank, and the old compressor pump with a new sureflow. A new tankless water heater replaced the 6 gal. and a couple of deep cycle batteries were added in order to reduce generator time.
I'm going to put a decent air mattress because it can go away when not in use, and if you add a 2" thick piece of really good foam, it's incredibly comfortable (I slept on this set-up for five years when I full-timed in my '64 Avion H-24.