Hi All-
The adjustable stem is an excellent idea. My concern was for fitment problems that don't have an easy solution...like a top tube that is too long or too short. If the intention is to ride 100 miles per day, everyday, until the journey is complete...perfect fit is essential. That will prevent numbness, blisters, muscle pain, and a bunch of other things that could knock one out of the event. I'd want the bike all dialed-in, coupled with a fresh overhaul by my trusty mechanic before departure.
Personally, I would check with UPS/Yellow Freight/FedEx to determine costs on their cheapest shipping methods since you would have the advantage of four months of saddle time on the bike. I call it "cheap insurance" and one wouldn't have to invest in a variety of adjustable components.
~ Blue Jays ~