Any of the social rides I've done with the Seattle Randos, where we stop at 3 coffee shops in 100k.
The Tour de Donuts started at Peet's Coffee and Tea (Redmond), wandered through the Carnation Valley for a stop at the Snohomish Bakery, then headed back to Redmond via Tolt, for a stop at Sandy's Espresso. We tend to navigate by food stops. Mark T. especially.
If there's 1 ride I have to claim is my favourite, though, it's the
25 mile Lake Sammamish loop, following the course from the Flying Wheels Summer Century.
There's some good climbing in there, but nothing too hard. A few fun downhills, resdential/park-ish streets for over half the route, and even the section on E. Lk. Sam. is pretty nice with the repaving and widened shoulder/bike lane. Just be careful of the root heaves on the little segment of the MUP from when you cross the I-90 bridge until you get back onto the roads.