V2 is an alternative
I like a track closer to V2, then over stampede pass and into Auburn. If the overcast is high enough you can get through stampede pass. I little lower clouds and the hair pin turn around snoqualmie pass at 3500 is possible following I90. But beware, there are some dead end canyons there if you don't follow the highway. Also, the clouds can pack up against the west side and you don't want to turn the corner and find solid IMC. A short cut over snoqualmie pass is to follow the saddle that the power lines go over. If you can see all the way through to puget sound, then things are clear.
If it is marginal vfr, then the Columbia river gorge is the best bet but be ready for some strong winds in the gorge, turbulence entering from the west, like negative G's, and low clouds on the west end.
But shouldn't you be heading north east next week?