Ok so head up highway 2 and keep going past skykomish. Just past that town you will see the ranger station on the left. Foss river road is about 1/4" past the ranger station on your right(if I remember correctly there is a little store/mocha stand on your left just before the turn).
Once on foss river road follow it. You will make a sharp turn and over a one lane bridge. Now if the road has no snow on it be careful as I almost dropped my truck trailer into the damn river last year. So once over the bridge and the road bends to the right/straight away you will probably see a few tow rigs/trailers parked along the road (typically where we unload with decent snow).
In any case once you unload just continue to follow the road. You will go under the railroad tracks(left bend in the road) and then uphill(large parking area to your left). Follow the road till you come to a big Y. At that Y turn left and just follow the tracks--once you hit that road you won't have any problems finding us.