During the summer you can drive up to the summit of Loser Ridge and there are two ways up. One that requires a great deal of fortitude, 4x4 and a good deal of clearance. The other is the "easy" way that you could get up with a normal vehicle. Ask me which one I took up ;)
After getting off I-90 at Exit 62, you'll go right on Stampede Pass Road. You'll follow that for 3/4 of a mile till you hit Lost Lake Rd. You'll take this for a bit - watch out for the massive ruts in the road. You'll hit a T of sorts and follow it left onto NF-5480. You'll drive for 1/4 or so and you'll cross an old wood plank bridge (watch out for the massive ruts on the other side). After you cross you'll see a sign on the left for NF-5483, you'll want to take that road. This is the "friendly" route up. If you continue on 5480, you'll make it to the top, but parts of your rig might not.
The rest of the route is a touch difficult to explain, so I attached a google maps route from Bellevue WA. The google maps route for some reason stops you short of the summit, but you can drive all the way up to it.
Correct Route from Bellevue WA
Once you get to the top, there will be an area to park and the activation point will be to the right of it.
After I got my gear setup, I seemed to have a mainline into Montana for activating. Stayed for roughly an hour (weather was starting to get bad) and ended with about 30 contacts. There are amazing views when the clouds break, so definitely worth the venture up.