RE: rc snowmobile
I think 136 was the original track offered on the first RMK's, we have evolved much since obviously lol.
I live in the sierra nevada, 3 foot powder days are not uncommon, and thats at my house and mountains go up another 3K feet.
my 144 '2 is a little short for things and i dont see many sleds around here under 160 anymore. but as long as you keep the power and momentum on you can do very well, ii still prefer the shorttrack because of the dirt bike feel and more power can take you where a simply adding a longer track can most of the time. and also hence why i added a 1/8th brushless system to my RC snowmobile, since i cant add a longer track all i can do is add more power and keep her up on top, but more power just completely overloads the tranny design,
actually since you mentioned trail riding, the art attack is not a bad rc trail sled, the rear suspension seems to be quite bouncy and hard to realy get smooth, other than that it would work ok for doing a little trail running, it does not realy have any kind of metal chassie, it well not take the abuse a regular RC truck can, the chassie is all plastic, and after motor and batterys your up to 6 pounds or so, that does not work out well. but if you take it easy and no fast jumps or running into stuff, it would be pretty cool for you.
werid for me i never got into fast trail riding, i can ride a dirt bike like hell down a trail but a sled is just werid as hell to me, i would totaly dig a Sled track with jumps (close one is like 5 hours away) but if im hauling but i dont want to be anywhere near a damn tree! and thats about the only thing i see when i haul on a trail here, so i just get out to the upper mountains or in the powder medows and act stupid, we actually have a dirt bike track here im gonna get my sled to this year, it gets allmost as much snow as my house, so at least for a while some nice clean jumps, no fences at all so im good.