Lay off the steel wool on chrome. I would take the headers off and take them to a metal polisher. As far as rust in the tank, I did a nasty rusted dirt bike tank with Metal Rescue with amazing results. You can also take any rusty painted pieces you want clean and dip them in Metal Rescue since it doesn't hurt paint. As far as your gas line, it might be rotted on the inside. I had that happen on a bike that sat for 6 months. It was due to the ethanol in the gas. It sent gooey rubber into the carb. This was one of only 2 bikes I could not get to run out of 23-24 I owned. I ended up taking the carb to a good shop that has a tank that had the good stuff for cleaning the carb. On an old bike, the worn gear type clamps look correct but I would stay with the oetiker clamps. You definitely want to open it up and check the clutch plates. They can stick together even though it feels like it disengages. I was surprised by this one time and one time only. Yeah, fire it up, warm it up, click 'er in gear and YIKES!!!
I don't know jack schidt about Harleys but I think that would be a fun project. I have gotten lots of old dirt bikes running and riding.
