There's a lot of great ideas posted so far. however, looking at the pristine condition of the vehicle, I would hesitate to do anything that would remove it from OEM. I know that the safety upgrades: disk brakes, dual brake MC, etc... are important, but your 40 could be a rare OEM driver that rarely exists. Anything that is rubber in the drivetrain will have to be replaced eventually, and all the maintenance checks with all fluid changes, grease, etc.. will be needed. It'll probably start leaking a small bit as it has sat for 40 years, and the drums are a pita. But...Very few people have gotten a 'Cruiser that is as close to OEM as the one you have. I would suggest getting it clean, shine the patina?, and drivable, use it as a grocery getter for awhile, take it to some car shows and TLCA meetings and have folks drool over what OEM looks like.
best, ty

best, ty