Frankly, many boats aren't as Catalina made them anymore. Mine's not. I've got a different traveler, different rigging on the main sheet, and Gerry D. never though about an asym spin when he designed the C-30 but I fly mine quite a bit, etc.. So some of what you may want to know will fall down to "figure out how this xxxx thing works."
Systems are pretty simple and share a lot with the C-27 and C-34 fleets. Stu's links are always very good. Rigging is whatever works. Parts are completely available here (SBO) or Catalina Direct if SBO doesn't have it. There are at least 10 other folks in your marina with a C-30 - so make friends. On just my finger in the marina there are 5 C-30s. 5. I think maybe 10 total sailboats (and 20 or so powerboats) - yup, the C-30 is a popular boat.
Oh, and it's winter. We (SBO forumites) have been reduced to looking for cars in pictures of snails, so we may really wanna talk sailing. So feel free to ask here. Lotsa folks not doing anything will be happy to respond. Heck, I'm at the end of 2 wks of Santa Ana's and am in massive withdrawal from sailing. Think I'll go this weekend no matter what. Looked at the log and it's been 20+ days since my last sail... gotta take the boat out.
The C-30 is indeed a fantastic boat. It's a great day sailor, hellava good weekender, terrible bluewater boat. Sails well, is forgiving, and will never set any speed records. But it's that fantastic "middle-of-the-pack" combination that made it the #1 produced inboard sailboat of all time.