Go to Dixons, great advice. They will set you up. You want real BP forget about anything else. FFFg is all you need in the barrel and pan, if you want to use FFFFg in the pan Dixon's will sell it by the 1/4 pound which is all you'll need.
While your at Dixons I recommend you purchase a dozen or more hand knapped English flints that fit your lock and a nice range rod. They will have all the shooting supplies will need. It is one stop shopping for the traditional muzzleloader.
If you need advice on cleaning it shoot me a PM with your email. They are very quick and easy to clean regardless of what you may think or heard.