I _think_ this is called the Snoqualmie South Fork road (at least locally/colloquially) which is more interesting than the N Fork; rode my motorcycle there years ago and it was fun but pretty crowded. The N Fork, a 1 out of 10 but is dirt, has a great shooting area near the end, some great camp spots on the river and is ~12 miles long. Not challenging but a "quick fix" if you only have a few hours. Last time we were on N Fork there were signs saying no shooting but I don't know the current status of that. A guy at work likes to go out just past Snoqualmie ski area and exit just after Keechelus lake; supposed to be good stuff to the W of I-90. Check out @RainGoat's links above - really good trailfinder resources.One good, moderately challenging forest road I found off of Interstate 90 is Forest Road 9021-110 in the McClellan Butte area. Heading eastbound on I 90 take exit #38 (SE Homestead Valley Road) towards an area known as Garcia. Fairly rocky and steep but generally doable with high clearance and good traction control. You will get moderate brush pin striping. Ends where the road has been blocked by a landside with a wide turnaround loop, fire ring and potential camp spot overlooking a scenic canyon. I'm no expert but I'm going to say it's a 3-4 on a 1-10 scale.