Now that my official report is out of the way, here are my personal thoughts:
Sounds like a large amount of semi-sorted, old brick. It would be particularly difficult to reconstruct sets for the set collectors (and perhaps even impossible given the missing box). I’m guessing the estimate she got was assuming Bricklink set resale prices. In my opinion that’s not really valid in this case if the parts are not divided as such.
It’s a lot of older castle and space stuff. In principal I’m interested, but I’m not currently looking to sink substantial cash into expanding my collection.
If anyone is interested in going in as a group I might join, but this is at least a LUGBulk-esque investment cash-wise (though delivery would be quicker!).