Dan,
Welcome to the forum. I have a 76 cb550, as well. Great bike; you'll enjoy it!
Pretty much the consensus when you pick up a new old bike is that the first thing you should do is the 3000 mile maintenance. It will possibly solve any bugs you are having (with idle, etc.), will give you the heads up on any potential issues before they happen, and, will familiarize you with the bikes operation/mechanics, so when something does act up, you'll be in a good position to diagnose and fix it. There's a shop manual on the faq page that you can download, but you should also pick up a Clymers or Haynes to use for reference. It sounds like you know what you're doing, but if you run into trouble, there's a ton of info on the forum if you search, and if that fails there are a plethora of helpful folks will be ble to help.
Where in jersey are you? I'm in MN now, but spent 6 years in Lawrenceville. Used to love riding to the shore at night when there was no traffic...
Cheers,
G