I came into this sport living in an area with near zero local access to Anything BP related and even hostile to unmentionables (however unmentionables and accessories were and are readily available in every city)
It really sucks for BP in Southern California; stuff was not just "hundreds of miles away" but Thousands of miles.
BP was hit and miss at only ONE (1) firing range, lead ball was either order online or make your own.
Flints?
Rendezvous were 300+ Mike's away just a few times a year, no local source in the crumbling granite hills, No local shops even knew what 'flint' is - so you order on line and grab some at Rendezvous when you can.
Patches? Make your own, easy and no brainer.
BP? Order online in bulk and it's much cheaper then the Scalpers at gun shows, also order with local clubs (watch out for cheats, listen to others - just make your own order).
Not having a local source for muzzleloading supplies is Not a misfortunate one off but is the Normal.
Those who live next door to their favorite vendor think they are the 'norm' and some live to strut around like a peacock about it....but you and I know; We are the majority and only the strong and resourful survive!
P.S.
I have since moved out of Southern California, to a 'Gun Friendly' state....Still NO Local BP supplies, but Scalpers are abundant!
But, still I keep my store full, even through COVID I kept both rifle and revolvers running