I am not a fan of paying for bike rides, but having several friends who swear by the Cascade Training Series (CTS), combined with a lack of motivation to do long bike rides without the motivation of participating in something like CTS, led me to sign up.
Week 1: Cascade Bicycle Club HQ - 26 miles
Week 2: I skipped to use some free tickets to go on a Skagit Valley Tulip Tour.
Week 3: Eastside urban loop from Bothell Park and Ride - 40 miles
It was rainy for about 1/3 of the ride, but I'm glad the only rain gear I wore were my lightweight rain jacket, visor, and shoe covers. I think I would have been too hot with rain pants on.

Week 4: Full loop around Lake Washington from Renton - 50 miles
I tried lowering my seat for this ride. According to Anna Ruby, this may be why my IT band (edit: it may actually be my vastus lateralis tendon) and knee were in excruciating pain after mile 5. I will try raising the seat as high as I can handle when I go on a training ride during the week.

Map of the route.
Elevation profile.
Week 5: Along the north - 55 miles
Raising my seat seems to have helped a bit. A fellow rider also reviewed my biking stance, and noticed that I toe-drive with my left leg, and not my right. I tried very hard this ride to keep my foot flat. As a result of implementing both of these things, I was only in a lot of pain for ~5-10 miles of the ride (discomfort for ~45 miles), compared to being in pain for nearly the entirety (50 miles) of the last ride.

Map of the route.
Elevation profile.
Map of route.

Weeks 6-9: Vacation/work travel!
Yes, I skipped four weeks in a row due to vacation work travel. Will I be able to do the 80+ miles needed next? We shall see.
Interlude: Flying Wheels
I originally thought Flying Wheels was happening during my vacation/work travel, and I would have a CTS day right after I got back from my work conference. That was not the case. It ended up that the Flying Wheels event, a popular route from Marymor Park just east of Seattle, would take place my first weekend back. I did not sign up for the Flying Wheels event, since I had thought I would be gone, and originally had plans to hike. But then my coworker invited me to ride with her at the event, and then ended up not feeling well enough to ride, so I took over her bib and just did it on my own. If we had done it together I might have gone for the 75 mile route, but alone I was feeling particularly uninspired and went for the shorter 46 mile route. I was exhausted afterwards, so I think that was a good call.
Week10: Kent-Enumclaw 92 miles!?
I made it through this ride with sheer determination. I did not face the knee problems that troubled me during weeks 3-5, so that was helpful. The most difficult part was a 20 mile stretch where we were cycling around 16mph into a headwind (our official speed is 12-14mph with no headwind). Speed is probably where the gap in my training really shows. Hills? No problem. Go fast for an extended period of time? Eeeeh. The other riders did just fine with the faster pace.

Map of route.
Elevation profile.