Just wanted to give an update on how my experience getting a return test at Anaheim City Hall went (spoiler alert, it went really smoothly). I booked the one hour NAAT in advance from the website that was posted in this thread. They said they take walk ups, but while I was there they were having people book their test on their phone and show their order number before they would let them come up anyway. I also overheard them saying that they had limited machines to process the tests on site so booking in advance would ensure that you can get the results in an hour.
I took an Uber to City Hall from the Tropicana where we're staying. It was like a 5 minute ride, super close. When I got there I stood in line waiting for my turn, then they checked me in with my order number and my passport for ID (not sure if passport was needed, but I had it on me anyways since Disney doesn't take Canadian drivers licenses in general), then I got in another line to wait for my turn to get swabbed. The NAAT is just a nostril swab, not like the PCRs that go further back.
After that my boyfriend and I (who had tested positive with a breakthrough case just over a month ago so he did not need a test to travel) walked to the Packing House to get lunch and wait for my results. If it would have came out positive I would have just walked back to the hotel (Google says it's about a half hour walk) but thankfully while we were finishing up eating the results came through and were negative! Just a heads up that they ran a rapid antigen test and the NAAT. I was a little worried as the text they sent only mentioned the rapid test, but both antigen and NAAT results came to my email. They did land in my junk email folder though so make sure it check there if you don't see them shortly after the text. It was then easy to download the pdfs, and I'm hoping all will continue to go smoothly tomorrow when we board our plane home.
Even though California has been amazing, I'm very happy that I'm not stuck here in a hotel for 2 more weeks.
If anyone has any other things they're wondering about the City Hall testing process feel free to ask and I'll try to answer if I can.