Your going to get a lot of pavement monkeys who have never seen 500 yards of open space spouting whatever info they read in the gun rags about "what is the best trail gun".
Pay no mind to them.
I've done "10 Miles In" bare hikes into the Ocala Nat. Forest with nothing but a High Standard .22 and a Claymore bag filled with a tiny bit of bare essentials. The perfect trailgun is a tough call, and depends a lot on where you are.
The man in Alaska that may encounter brown Bear is best suited with a .44 Mag or better (And if I were him, i'd go at LEAST .454 in a sidearm)
If you want a gun that will double as a hunting arm, a 6" .357 is about minimum for deer sized game (My primary trail gun is a 6" .357}
If you would see yourself shooting mainly small game, a good .22 is a must (Although, a lightly loaded .38 Spec gives you more punch, and can still cleanly take small game if you can make the head shots)
If you live in an area with snakes, a revolver is best, since they eat shot loads with impunity....
Really, the best trail gun is completley, entirely dependant on your locale, and your ability with the arm. I am so confident with my High Standard, I was willing to pack 10 miles in, carrying only a wee litle .22 pistol- facing the possibility of Dope Growers, Hogs, Florida Cats, - not to mention I had to feed myself with it.
Figure out what your needs as an outdoorsman are, and THEN choose the best all around chambering.