In a revolver - for lighter - I would go with a 4" gun, in .357 mag. I would stay with a steel gun / the airlights are very tough to shoot for most people ( they walk around in your hand as you shoot them - and some of them have terrible triggers in them ). A S&W model 19, 66, 686, etc are all good options / I favor the older models over the newer models with internal frame locks.
In a semi-auto / I would probably recommend a .40 S&W as an in between option for a caliber. Something like a Sig 239 - single stack, 7 round mags - is pretty small and relatively light.
When I used to back-pack and hike in for fishing, etc / I oftened carried a model 28 S&W 6" .357 mag / 10 - 20 yrs ago I began to carry a 1911 5" in .45 acp - but those are both heavier options. If I was in Grizzly country - Northwestern Montana or Alaska - then I went to a .44 mag in 6" - but again its a lot heavier.
In a semi-auto / I would probably recommend a .40 S&W as an in between option for a caliber. Something like a Sig 239 - single stack, 7 round mags - is pretty small and relatively light.
When I used to back-pack and hike in for fishing, etc / I oftened carried a model 28 S&W 6" .357 mag / 10 - 20 yrs ago I began to carry a 1911 5" in .45 acp - but those are both heavier options. If I was in Grizzly country - Northwestern Montana or Alaska - then I went to a .44 mag in 6" - but again its a lot heavier.