IMHO, you have four choices (five if you consider selling it and getting something you like better).
1. Do only what is needed to prevent further deterioration.
2. Restore to original (make it like new)
3. Restore to, so called, museum standards (like restoring a Ford Pinto to Rolls Royce standards)
4. Hot rod it. (anything that does not look original, including non-factory looking paint jobs)
Value to serious collectors from low to high goes something like this: 4, 1, 2, 3. However some purists would not even consider it in any condition other that 1 or 2. You also have to realize that 3 is very expensive to do, and you will never recover your cost of doing it. Thee are also collectors who want things to look old and beat up, but in my experience they also want it cheap so I would not base my options on them.
If one is a collector and wants to ride it 2 is probably the optimum cost/benefit option.
If one has no collector interest 4 is a lot of fun (if you want to retain some of the collector value, do nothing to it that can not be undone, and keep all the original parts).
The exception is that if something is 30+ years old and like new it will be most valuable if kept in that condition, especially so if it is relatively rare.
The general guidelines above apply to almost any collectable, BTW.