Steve,
I'm in the same boat as you, and I'm in Orlando so hit me up if you ever need anything. My 75 550 is in good shape and runs well (besides a slight oil leak), but the things it needs replacing are expensive items.
1. the factory exhaust looks almost new except for slight pitting in the chrome and a glaring hole where the silencer meets the header.
2. The seat has a non-oem cover and is ripped and looks like poo.
3. The frame has some light pitting so it will need to be stripped and powdercoated.
4. I have the original title where the original owner signed it over to one guy who never transferred it to his name. He since then sold it to someone else who sold it to someone else, etc etc and no one transferred it into their name. So i've got a bunch of bill of sales from owner to owner but I am missing one bill of sale so it kinda of makes the whole thing FUBAR. I just don't know if its worth it to restore a bike that I might not be able to get a real title for (besides the ITS title - registration thing).
Other than that the bike is great and is 100% all there. I wanted to cafe it at first (and I still do), but I think its close enough to original that I should keep it that way (especially if I can find a replacement silencer and nice seat).