Kevin, I think the answer is "Everything".
Once years ago, I was heading back to Friendship and I planned on doing some shooting while there. I had one of the October Country Traveler bags which is a big bag. I had in it 2 boxes of .530 ball, a can of Ffg powder, a pint bottle of bore solvent, a couple of tins of caps and whatever other stuff I figured I might need.
Frankly, I have never cared for shooting boxes and don't own one. I figure I can get everything I might need in a bag, and if I don't get it to fit, I don't need it.
Of course, after I got there I emptied it out. I think it weighed about 32 pounds all told. Much too heavy to carry around.
Tom, that's a great photo. Only way it could have been better was if it was taken a millisecond faster and captured the fire in the pan or coming out of the vent. Looks like it was a fun day.
John