How Much More Is There?

So one question that I'm having a hard time answering is how much story I have left. For the most part, the story beats I planned from the beginning are the beats I'm using now, but they've been fleshed out significantly in the mean time. The thing is, I've developed more the scenes that I'm closer to writing.

It's like in a video game, where the background objects may only be a few pixels high, but up close they're rendered in exquisite detail. The result, however, is that I have a hard time judging how much story there is left. As I get closer to future plot points, they get more developed, and it turns out there's more story to tell than I expected.

I can't say that I'm the only writer to have this problem. It's almost a cliche for the fantasy author to start out writing one book, that becomes a trilogy, that becomes a longer series, and seems like it's never going to end. The author swears to his audience that he does have an ending in mind; die hard fans believe him, detractors say he's making it up as he goes along.

But he does have an ending, it's just further away than he planned, and he really, really wants to get there because it's such a cool ending. Well, that's the position I'm in now.

I'm trying to ask myself now if I'm really in Book 2, or if I'm still in Book 1, or if that even matters. Are there three books in the series? Four? One giant one? I have no idea at this point, and I think that's okay.

So what I'm going to do is this... go on as if I'm writing Book 2, and when I get enough of a word count and reach a point of closure, move on to Book 3. If that ends the story, great. If not, I move on to Book 4, or whatever it takes. Then I can edit together the text into whatever volumes seem appropriate.