the triple crank/one cog bike was the one I used a deraileur on- it doesn't exist anymore 'cause I kept bolting stuff on to the bike and now it's a utility bike with a 7sp rear. I think I might even put the front derailleur back on so I can shift on the fly 'cause it's hard to hold up a loaded bike and put the chain on another ring at the same time. ANYHOW... not only do you need to run a tensioner, but I think it has to be a derailleur in order to run the 3 ring/1 cog combo- unless there's a tensioner out there that will take up 20T worth of slack!

PS- is the snow ride fixed-only? My fixed is still in the "project" stage due to budgetary constraints, but if mountain bikes are welcome I'm in!