I've finally got some progress to report.
First of all, I've got adjacent sims and their prims loading. First screenshot shows that, but you can see gaps between the terrains of the 3 sims. Second screenshot is from the opposite angle, showing the terrain being stitched, so no more gaps now.
Second, I don't have any recordings of it yet, but the'll be coming in the next few days, physics objects now move a lot more smoothly. As such so do avatars. Previously there was an illusion of it being lower framerate than it really was due to some bad math on predicting the movements of objects, but that's been fixed.
I'm currently waiting on LibreMetaverse to update their library to include some recent changes we've submitted that allow for the extra data from OpenSim VarRegions regarding their size. Once I have an updated LibreMetaverse I'll be able to integrate it. In the mean time I'm going to work on cleaning up avatar appearance, but I suspect it'll only be a few days at most before I have an update for it.
Further updates in August will be patron only.