I've read much of this period and most specifically the frontier time of 1750-1800 on the Ohio Valley. Your 5xgrandfather would have been in some wild areas at a time when large game (buffalo, elk, moose, brown bear) had largely been driven out as well as the big cats and wolves, although some big cats and black bear still roamed. This was a time when the long rifle had grown more slender, elegant, and embellished in appearance. The bore sizes had shrunk too as the need for firepower was less, the average for Revwar rifle bores was in the neighborhood of .55, while the early eighteen hundreds started to see bores of .30, .32, low forties and everything in between, .38 was incredibly popular as it was big enough for deer sized game and could be loaded ligght for small game. I've read of people hunting black bear with .34, and John Johnson managed in the western frontier with a .30 Hawkens for years--even killed to get it back rahter than aquire another gun of larger calibre.
As for the clothing fringed frocks would be okay, although later in the 1800's not so common, breeches of various patterns would suffice and any frontier or colonial pattern shirt would suffice as folks in the nether regions tended to aquire what they could or make copies of what thye had out of material on hand. I've seen a drawing of a very fancy officers coat from Revwar that was made entirely out of buckskin. His coat wore out so he used it as a pattern for a new one oout of the only readily available material. Blanket capotes were common from 1700's up through the 1800's in various cuts.
I'm out of time, I can get more specific later, I'll get the names of some of my sources to you if you like.