The 327 TTR8 is a wise choice. The neat part about the 8-shot Tactical Rail Revolver is it's design to temporarily affix a top and/or bottom rail.
Smith and Wesson designed the scandium N-frame for the lead penetrater on door entry teams. Typically, the top rail carries a red dot optic and bottom rail a light (laser)
I'm not sure where you will be hiking and camping, but your most vulnerable time will be night, between dusk and dawn. That's the time I've seen a large black bear near my bedroom window, some 30-40ft away. Here, it's a time to be wary of rattlesnakes, don't expect snakeshot to kill a rattler. This Mojave rattler was hit three times behind its head, muzzle about three feet away. Finally one 125gr SJHP shot behind its head separated it from its slithering body.
I have a great deal of respect for mountain lions, in a defensive situation, the lion will be facing you and you will be making a frontal shot. During daylight hours I only get a fleeting glimpse of the big cats; however, at night they have faced me (and dog). I had a big cat come toward me, angling from 125yds to about 85yds; between its large yellow eyes was a laser light, reluctantly he walked off. Next morning I went out to wear the l lion had been, the range grass at that location was 32 inches high.
Mountain lions are capable of a 30'-40' horizontal and 20ft vertical leap distances; in fact, mountain lions t-boning elk can cause its neck to snap.
Here, there's lots of brush along the sides of canyon/mountain trails. Be aware of wind directions and remember, lions will leap over brush and charging bears can run through it.
I carry 686s and M29 Mountain some of the time, also 1911s in 38Super and 10mm, typically in a Galco vertical shoulder rig, wheel guns in a Bianchi X15.
A G20 loaded with 200gr WFNs comes highly recommended for your needs should you not choose a 357mag.
Enjoy