If its a '78, its a 550, not a 500.
Best place for manuals is this forum-
http://manuals.sohc4.net/cb550/A very good website as a resource for factory part numbers, assembly drawings, etc is:
http://www.cmsnl.com/honda-cb550-four-cb550k3-1977-usa_model1015/partslist/Buy the factory parts locally, but use that website for reference purposes.
Avoid buying anything with a brand name of "Emgo". If you rehab your carbs, do NOT change the stock brass with aftermarket kits.
You want to buy a decent set of "JIS" screwdrivers or bits. Every "phillips" screw on your bike is not a Phillips, its a
Japanese Industrial Standard and its rather different. Thats why they get wallowed out.
Ample members in the Carolinas, GA, TN, VA. The "Members, Search For..." link is here-
http://forums.sohc4.net/index.php?action=mlist;sa=searchMay or may not work always.
If you need spare parts, they're always available from a member somewhere. Post a thread in the SOHC Bikes or Project section, or in the "Wanted" section or scan the "For Sale" section. Easy enough.
Bike only weighs about 450# soaking wet, so the HF trailer is fine as long as its not a "front wheel tow" only. Secure with 4 straps, 1 at each corner and cinch them down tight enough to compress the suspension while trailering it.
Welcome, and post some pictures up as soon as you can!