Great advice here, particularly the chamois butter and riding past 100 miles the first day. We always stayed in Toledo. By going 120 +/- miles the first day the second day, when you're really tired is enough shorter that it seems easy. We've done STP 4 times, twice in two days and twice in one day (on tandem). The one day is actually much easier a training time commitment. With the 2-day you must ride back to back days to prepare which is unnecessary for the 1-day. Following the Cascade training schedule really makes the difference. Another thing I think really helps is practicing taking short rest stops. If you let the rest stops be social they start eating into your overall time.
You're welcome to check out our STP training and ride reports at http://www.s2cycle.com (look under S2Cycle in the years 2000-2003).

Sheila