Trans Iowa started in 2005 as race across the state: on gravel, self supported, self navigated and underground. At 300+ miles and with a time cutoff of ~30 hours, this event is truly for the nutty, but it has proven to be a very popular event.
The route changes every year and is kept secret until cue sheets are handed out minutes before the ride begins. Earlier versions crossed the state, but the route has evolved into a loop format. Version 4 (2008) was based out of Decorah, but the start/finish will move to get more of the “Trans” back into Trans Iowa!
TI-V3.gpx – Version 3 GPX data from planning stages (complete loop from Decorah)
(Thanks to David Pals)
Also, head over to Motionbased (search terms “Trans Iowa”) to find a few Trans Iowa GPX files from V4 of the race. None are complete, but they will give you an idea of what to expect and something to look at in your favorite GPX app.