Depending on group preference this trip is very flexible. We could even make it a one way 3 day trip to Ellensburg with 2 nights of camping. This would require rides home to Issaquah area. The entire trip is on dirt trails (very well maintained) with the exception of about 5 miles of side roads with almost zero traffic. This isn't a difficult ride if you are used to the mileage. Obviously on the west side of the cascades it is a very gradual uphill. On the east side it is a very gradual downhill. One of the highlights is the 2 1/2 mile long tunnel underneath the summit ski areas. We can visit Snoqualmie Falls if the group prefers. Kids Ok.
Fees for 1 night would only be for camping at Lake Easton State Park hiker bike sites. Or depending on group size we could stay for free at an old logging camp.
This is a very flexible route with 1-3 nights and different starting stopping locations.
My wife and I are in our late 50's. It isn't a race! It's about enjoying cycling and the outdoors.