DPS, Rob--Thanks for the useful information. The main reason I was considering Vantage was because it's right off of I-90; After we do the tourist thing in Seattle, we're heading East to Montana, though it sounds like it'll be worth the extra driving time to go to Leavenworth instead.
The way you guys talk about Vantage, it kinda reminds me of a crag local to me (Georgia) called Lost Wall; it's climbable, but kinda crappy and incredibly inferior to T-Wall, which isn't much further away.
-Steve