It's very possible the price will fluctuate a lot over the next 10 months. There are a lot of airlines who can offer a sale and immediately influence the price. I'll let others with more experience offer a suggested price to shoot for and/or drop-dead date to book.

You could certainly change your routing if the schedule changes significantly, and if there really is time, you could always pay the $50/pp to Same-Day-Standby/Confirm on the connection. I believe they will allow this after all the international segments have been flown. OF course it can be tricky with baggage, which I'm sure you will have for a month long trip.

Something else I was wondering about, considering your just a regular member, and you're paying cash, would you consider flying AA, UA or EI?