http://www.burlingtonrotarynj.org/co...Rotary_100.asp
This is a good one - not real crowded, varying lengths up to 100 mi, start times from 7am until hours later, nice country, etc.
Bring plenty of fluids, tho - not a lot of food/water/rest stops. Decent feed at the end.
Cue sheets etc at link (if link doesn't work, Google Burlington Rotary 100). $40 day-of-ride signup.