Stay cool before pulling the trigger...
I'd not go over about $500 for it. Else I'd go buy a straight-up 686 4" for $400 or a touch more. Then I'd have money left over for a nice shoulder rig, a cross-draw belt holster, fancy grips to customize it to my hand, and some ammo to practice. If "packability" is what you want, get a 2.5" 686 - it will have the round butt regardless of the dash number, and you will give up little or no accuracy and only a little bit of muzzle speed; not enough to matter on anything but a grizzly. I have both a standard 686 4" and a 2.5" and I sure like packing the snubbie better when in the field. When I lived in Indiana, it wasn't grizzly territory, so I'd be OK with that!
Also, at the $500 level, I'd be equally tempted to get an N frame, such as a high-quality 28 or a good deal on a 27 (I bought a 97/98% 3.5" 27-2 this spring for $500 total in a local transaction). Good deals are out there once you start looking.
All that said, a 686 mountain gun is a nice piece, but at that price not at all a "value" or good deal. To me, once a 686 gives up the full lug, it looses it's major virtue over the K or the N - the ability to tame recoil better with that lug out there adding muzzle weight. Once you strip that away, like on the 620, then I'd rather have a nice vintage K frame, or an N frame like a 28 or 27.