I'm at 30000 words with two gaps in the middle that are basically '[more stuff here]' and no sign of an ending. I often stumble on endings, so I'm not as worried about that as I might be otherwise. I mean, I am worried, but I might find an ending another thousand words along. Or not. The gaps worry me a lot more because I have no idea at all what needs to go in there.

I'm mainly worried that the combination of length, timing, fandom, and subject matter means I won't find a beta reader. I'm not as worried about SPaG as I am about consistent characterization, finding unfired Chekov's guns, etc., and all of that is vastly more time consuming for a beta reader and generally harder than SPaG.