Singerco.com has free downloadable manuals in the resources section. I recommend having a manual handy. These machines are capable of a lot if you know how to use them. The downside is they're not overly intuitive to set up and use.
Look for the black Singer "tophat" cams. They're easily available from sources like Ebay and were used from the 400 series slant shank machines thru the 600 series Touch & Sews. The Touch & Sew ones tend to run a little cheaper if you're not worried about a matching box for your accessories.
Sew-Classic.com has new slant shank feet along with other maintenance items like bobbin winder tires. They also have a good reputation here.
Congrats on your new Rocketeer! I have a 400A and a couple Touch & Sews and like them. Yours should be a good machine.
Your 66 is a great machine for piecing. It would be worth the effort to make it run. My first 66 is the machine that got me hooked on vintage machines.
Rodney