Glad you found the barrel at a good price!
As far as the "other stuff" you'll need, you're basically looking at developing a good load for your rifle. If you do a search of this forum, you should be able to come across many posts that tell what other people have found that works for them.
OR - you could start a post of your own, specifically asking what other Encore owners use - that way it'll be real specific to what you have.
Then there are all the acouterments - you'll just have to pick up on these as you go - or maybe find a good book or video to really get you a head start on muzzleloading.
Keep asking questions - and have a blast!

IM jaybe