The start time is negotiable
, but I'm thinking let's meet at Patty's Egg Nest in Monroe at 7am. I'm hoping at that time, we'll be able to get seated quickly. Whoever gets there first, gets a table for the other (and anyone else who wants to join us). Let's plan on kickstands up when we leave, so gas up prior. The ride is 8 hours minimum, so I'm thinking that's at least 10 hours with breaks and lunch. Probably more like 11. That'll get you home by 5pm, and I'll be home up north by 6pm.
Here's the route I'm proposing. https://maps.google.com/maps?saddr=Patt ... ,8&t=m&z=9
If that long URL doesn't work, here's a short version. http://goo.gl/maps/vVPYy
A few weeks ago, a trip like this was proposed by Julie D on the Meetup group. She proposed going through the Yakima River Canyon (WA-821 S). Lots of twists and curves. It sounded like it would be fun. So the route takes us from Ellensburg to Yakima on WA-821.
I'm assuming you'll drop off at about point F. Gas in Ellensburg and/or Yakima. Distance to Ellensburg is about 146 miles. Distance to Yakima is about 184. That might be stretching it, if you get on the throttle in the corners on the Yakima River Canyon road. From Yakima, it's about 130 miles to gas in Enumclaw.
Here's a picture from Google Maps at Chinook Pass to whet your appetite.