Not sure on total km..but lots. The off trail areas to explore from the groomed trails are massive…absolutely huge area of crown logging rds and bogs to explore. Most use a gps and I can see why.
The gas station at Smooth Rock seems to have many issues of running out of gas, that said they pump a lot of fuel there. Jeff said in his first post that they carry fuel and so they should be good to get to Kap or at least Moonbeam without any issues no matter whether they come up the C to SRF or go to SRF via Cochrane and the A trail.
Be aware between Hearst and Cochrane one of the towns is having fuel issues I believe it is Smooth Rock (dont hold me to it). They have had issues having enough fuel on hand for a few years. Just yesterday, I saw the ski hill in Searchmont said they ran out until tomorrow. Call ahead, on your route to verify. Also, after this huge storm today and tomorrow, it will take a bit to get everything groomed back down to passable. The Soo area and northeast of there is forecast to get several feet in 1 shot. Glad you guys are trying to get a trip in. Keep us posted, we may be up at the house in Dub, depending on your route, timing and weather. Ski