If you do take the Forestry Trunk Road, (and I think you should at least one direction--mainly gravel!!) fuel may be an issue. Don't skip any fuel stations if you have short legs. I brought a jerry can running that road on my DR with standard tank and needed it. Since my IMS tank mod though I will be OK in that area.
Some stations in that neck of the woods may not be open when you need them to be. There is fuel at Hiwood Junction east of Longview (worth it going that way...Hiwood pass is I believe the highest driveable pass in Canada or NA), Castle Junction, Cochrane, sometimes at Mountian Vew Lodge. From there is nothing untill Nordegg. Past Nordegg there is not much either. Cadomine might have fuel but you should be able to make it to Hinton where there is. Beyond that i don't know as I have never been up that way by ground anyway.
Oh, and if you go that way, do stop off at Ram Falls and take the short walk to the falls. It is worth it and you will want to strech your legs then anyway....