The consensus for cartridge seems to be hovering around .22 LR, 32 S&W Long, 38 Special - which makes perfect sense.
The advent of the .327 Federal and the Ruger SP101 chambered for that cartridge may turn out to be a game changer. I wish the SP101 was a tad lighter but the option of 32 S&W Long and two different magnum cartridges in the same stainless, compact gun is attractive.
The .22 gets a lot of love and that makes sense. You get a lot more ammunition in the same size/weight as the larger rounds. The S&W Model 63 embodies just about every trait that one would want - chambered in 22LR, stainless construction, small frame, good sights. But then we have the lighter weight options with some of the alloy frames but those tend to have some carbon steel parts.
The 38 Special has the biggest penalty in terms of the weight of the ammunition but shines in terminal performance. The 32's and 38 Special cartridges are reloadable, which isn't a consideration in the woods but is a consideration at home. I think if I was in Char-Gar's position in a very remote area for weeks at a time; I would want more ammo for the same weight. The 22LR is the winner in that scenario. Reloading cartridges would not be a consideration at all. However, change the situation to one in which you return to home every day and the reloading option becomes relevant.
The 32 calibers (32 S&W Long, 32 H&R Mag, 327 Federal) may be the best of both worlds. Small/light ammunition and reloadable cartridges. I wish there were a few more options in those calibers.
Thanks to all for the discussion - Keep it going.