I wonder if the Unofficial Patches for the DLCs are worth having as they are very buggy even with them. I've just started a new game and Catherine and Tobar the Ferryman came to Megaton right from the start. In fact, Tobar came into the Megaton player house and seems to plan to stay there. I had a similar issue during the last play through, when Catherine suddenly woke up my character in her sleep and wanted help - and when my char arrived at the ferry, both she and Tobar were missing. I've also had issues with the other DLCs. And it's not just a question of making a "clean save" without, say, Point Lookout and start over as several of my other mods depend on it.

Anyway, my question is if the Unofficial Patches help at all or if I even might be better off without them?

This does not happen to me, so it's another mod that you have. There is one mod that changes how you meet up with the PL folks, and it changes a bunch of other things too, so that could be causing this weirdness that you are experiencing.

One thing I did was clean my DLCs with FO3Edit, that increases game stability on a mod that references the DLCs, but that won't fix this issue. Either stop using that mod that changes PL, or play with your load order or Bashed Patch to get everything working like it is supposed to. Note, these Unofficial Patches have to load before any other mods do, and in the order of the DLC release.