Kimsch has posted a speed run of the original Ultima IV on YouTube, with the initial play-through clocking in at 2 hours 31 seconds and 11,051 moves. That establishes the baseline on which he hopes to improve with a follow-up video.
I’m still not sure if Ultima IV as ran under CUO can be completed solo, but it is my hope that someone attempts it soon. CUO does not currently track your move count, but this speed run has me wanting to add that in.