TL;DR: A+, would do again. Here's some pics: https://imgur.com/a/RH8c7Zm
It's been a week and I've had some time to think about it. I'll start off with that this was my second STP, but the first was in 2010, so it might as well have been my first. I'm in moderately-reasonable shape; I was a year-round bike commuter pre-pandemic (~30km RT, with ~300m of climbing on the way to work). I now work primarily remote, so my riding time has gone way down.
I had grand plans to train up to the ride, but the shitty spring and early summer weather we had in the Vancouver area, coupled with life stuff, put a dent in that. I did have to travel ~100km from home for a work conference last month, so I rode my bike rather than drive, so that was a good reminder of what a day in the saddle felt like and confirmed that my bike fit and clothing were still appropriate. I also have another single-day 160km ride coming up in a few weeks; it has way more climbing than STP, but it confirmed that I should be able to do it.
The big thing to remember about STP is that it isn't a race. Yes, there are a ton of hard-core roadies out there, and a non-trivial number of folks do the entire shot in one day. You'll also see a lot of "regular" people, older folks (especially on tandems), and even kids. If you need to get off and walk a hill, get off and walk a hill (just do it safely, k?). You'll have other riders cheering you on and encouraging you.
Any rideable bike is an STP bike, as long as it's in good condition, and is comfortable for you. I saw the entire range of bikes, from 5-figure road bikes that weigh less than my helmet, tandems, city bikes, cargo bikes, gravel grinders and more. More than one safety pizza and Party Pace sticker were spotted, and there was one x-biker who had a baguette voile-strapped to his top-tube. I was riding my steel-frame all-road Bike of Theseus (local-brand CX frame, with a bunch of parts swapped out over the years), Brooks saddle, and Gravelking SKs (43 front, 38 rear). And yes, the front basket stayed on; it was a good place to stick banana peels after the stops 😉. More than once I'd get passed by a peloton only to smoke them on the next ascent.
I found that I carried too much food with me, but that's my over-preparing nature. The entry fee covers a few official rest stops each day, one with lunch stuff. There's also a number of "mini-stops" set up along the route run by different school groups, service clubs, etc that sell food and drink, so bring cash (some but not all were taking cards this year). There's mechanical service available at the official stops, as well as some of the minis, and there's sweep vehicles on route if you have an issue. Weather this time was ideal, if maybe a bit on the cool side. Apparently the last one in 2019 was a scorcher, and the weather in Portland got pretty hot last week, so it was just fine.
If you're doing it in two days, you need to sort out your mid-way lodging. The STP folks don't run any lodging but they do list lots of options on their website. The official mid-point is Centralia College. You can camp wherever on the lawns there, and I think where was some indoor options in the gym. There's limited commercial lodging in Centralia, and it books up fast. A lot of people elect to ride further south on day one to make day two shorter, and there's options along the way (more public park camping, or churches and schools that open up). My partner drove down with me from Vancouver; we grabbed a hotel in Seattle for the night before, and camped at the SW Washington Fairgrounds on Saturday. It was… fine. Probably would choose something else next time. If you don't have someone driving (and if you do, it's imperative that they stay off the route, it's not safe to have your SAG wagon following), STP has gear trucks that go do Centralia and some of the other popular overnight destinations; it's included in the fee. I did see a few folks who appeared to be carrying their gear with them; not sure why other than not being sure how far they'd want to go on day one and not being tied into a particular destination.
The route is pretty decent and straightforward. It's well marked, and really, you just follow the bike in front of you 😂. They let you go from the start line in waves to space it out, and some areas of congestion (the first several km from the start, and around some of the rest stops) have traffic control, but other than that you're in traffic. It also goes through a lot of rural WA and OR, so yeah, be prepared for that. When it comes time to cross the Lewis and Clark bridge into Oregon you'll get held there; they'll stop southbound traffic so a wave of riders can cross and take the lanes. Watch out for the expansion joints on the bridge, some of them are nasty. To contrast, when crossing the St. Johns bridge into there's no control, you're riding in traffic on the bridge deck. The last stretch into the finish line in Portland is on city streets, so lots of red lights. I even had to stop at one right at the finish line (like, 10 feet away).
At the finish there's a beer garden and food trucks, as well as where you get your finisher swag. If you're using their busses to get back to Seattle, that's where you stick your bags on the trucks.
The ride is put on by the Cascade cycling club in Seattle and it's very well organized. They put on a couple of webinars (STP 101, STP 201) that give you a really good overview of the route and what to expect. There's also an active Facebook group, which is where I found the tip about camping at the fairgrounds. On day two I lost my phone/wallet at the lunch stop, and it was turned in and gotten back to me almost immediately. I also got an email from them on Monday telling me that they were holding a lost item at their office; somehow my NEXUS card slipped out of my other wallet that spent almost the entire ride zipped into a jersey pocket. That would have been a very awkward issue when driving up to the border to get home. Top notch organization (and a beautiful office, I recommend checking out the area if in Seattle).
To sum it up, it was a great time, and I'd do it again. Anyone can do this, just get out and ride your damn bike.