Well, I replaced the spark plugs, which were quite old. The previous owner didn't have spark plug replacements listed on his log so not sure when the last change was.
Then, I made a second attempt at replacing the upstream air/fuel sensors; this time through the wheel well. Turns out it's ridiculous no matter which way you go and I could not get an angle or leverage from any direction. I gave up on that job.
The brake caliper looked gross, so I cleaned and greased it. Hopefully it's not frozen again