With the packs, it's more along the lines of where the straps are coming down from my shoulders to the pack itself, and how that would impact a hip holster (but that's with any gun). Appendix may or may not work due to the terrain steepness and climbing up it. The terrain could be anything - muck, heavily wooded, 60* inclines, thorns everywhere, marshes and bogs, grasslands - short of something generated by mountains, I'm exposed to it.
Barrel length isn't the most important thing to me, in either shorter or longer. How it carries and how it shoots are my main priorities, as it's primary purpose will be a trainer, and secondary for carry (primary is a P226 for example).
The ease of dissassembly of these Rugers (and stainless construction) make me pretty comfortable if I need to disassemble and reoil in a hotel in the event of going for an unintended swim.
Interesting in this is the 2nd recommendation of the LCR over the SP101 - but the GP100 over both (if feasible)