There seem to be a few folks planning to start at different times. Here is a summary of options available depending when you get there AND want to start.
6AM/Sunrise. A pace of about 12:00/mile will permit a full loop to get back to Brownsville. For those looking for a 20 miler, this is usually the best option running 2 loops, particularly when its hot and sunny (not the case this weekend, but could be on May 20)
7AM (Lucas committed to leading this) Do a short circuit just shy of 5 miles that covers a few miles of the western part of the course beginning and end joined by overlapping the stretch of 2nd Manassas Trail that the RIWJ 50K normally does not cover. This will get anyone following this route at a 12:00/mile pace back to Brownsville for 8AM start. Course plotted here: https://runkeeper.com/user/lucasmoten/route/4604004
8AM (Most people will be doing this) The main training run event. 10+ mile loop. Course plotted here: https://runkeeper.com/user/lucasmoten/route/4319424
If you get there are few minutes early than any of those and want a short warmup, consider the starter loop. It's not plotted on the 10 mile loop, but can be used to make up mileage and keep you right at the picnic area so you dont get (too) lost. Or you can run back and forth along William Centre Blvd. Course plotted here:
Finally .. a quick shout out to Larry Mercadante and others from The Running Store group from Gainesville.. That group meets every Saturday from the Henry Hill Visitor Center at 7:30 AM. They usually have water set out there as well. Larry indicated that his last 20 miler is next weekend the 13th. This dovetails with the RIWJ training runes since we don't have an official one for next weekend. (They have a loop that encompasses the Battlefield and nearby Conway Robinson State Park in one big 16 mile loop, probably preceded by an out and back from Henry Hill to the Route 66 rest stop starting at 0645 for the other 4 miles).