Welcome aboard. Looking forward to hearing of your adventures. And photos are always welcome.
For moulds and other accessories, you might try Track of the Wolf, Dixie Gun Works, Log Cabin, The Gun Works, Cain's Outdoors and October Country. For Powder Horns, check with Powder Horns and More. Jeff Tanner in England makes very good moulds, especially good for big bore guns or for unusual sizes. I have had him make .990, .980, .820, .715 and .650. His response time is very good and his prices can't be beat.
John