Joe,
www.bbtc.org has a new trail wiki for PacNW trails, mostly Washington state. Also, I 'd recommend shooting an email to Jon Kennedy at BBTC.
You'll likely have to ride east of the Cascades or Oregon desert , as a lot of the high country Cascade rides will still be pretty snowy.
That Lake Chelan/Junior Pass/Entiat valley ride mentioned by MickeyD over to Lake Wenatchee & Leavenworth would be very nice.