I did both rides too. The incredible boredom of STP... will never forget. RSVP isn't like that! it's fun and interesting. I agree about Chuckanut, it's no big deal, very pretty. THe wall? HEH, I remember that. You might walk it. On tandem we went right up it. We did a ferry ride. we DID NOT have hot weather the time we went, so no complaints there.
I think if you can do STP you can do this one. YOu'll be tired at the end.