The engineer in me has devised the following word-counting strategy for your consideration:

1. Physically count three pages.
2. Compute average words per page (WPP).
3. Count pages (PG).
4. Multiply WPPxPG.

You won't be able to put it into the NaNoWriMo.org validator. You could perhaps cheat the system by copying the correct number of words from a previous work you've written and dumping those into the validator.

Second option: My current mobile device (finally!) has handwriting recognition software. I haven't experimented with it enough to determine how effective it is, but be advised that the technology does exist, however rudimentary.

Third option: Transcribe after handwriting. I would probably do this anyway for two reasons. (1) I'll need it to be electronic for submission or self publication, and (2) I find that transcribing my work is a great way to "edit" my first draft. During transcribing, my brain does a much better job of finding those perfect words and phrases that eluded me the first time. If you want your word count in time for November, though, this will only work if you don't edit as you go and you type quickly.

Cheers,
Michelle