I'll try to answer some of your questions.
I quick swab the bore after every couple of shots, I can only fire about 4 times before it starts to get hard to load. Plus swabbing keeps accuracy up. Yes lube is necessary on the patch. Folks here say a home cast round ball is just as accurate as a store bought swagged one. For a source for supplies, try trackofthewolf.com, there are others but I like TOW. If your barrel is clean and dry that rifle can sit loaded virtually FOREVER and still be ok to fire, provided it is kept dry. After you load a charge, patch and ball, you can swab the bore with bore butter to keep it lubed while sitting. www.powderinc.com
sells and ships as little a 5lbs of powder to your door. You MOST DEFINITELY need to use PURE lead for ML use when casting. And a Lee mold is a great product I like them. Take care of it according to the instructions and it will last you a long time.
Hope this helps.