KMack,
There are a couple of Rando routes that go that way. "Little Egypt", which is organized by George Evans, is 380K and runs from Rockwall to The Woodlands. The second is "Space Shot", organized by Dan Driscoll, is 427K and runs from Arlington to Katy. They are listed on texaspermanents.org, but I don't see maps for them. You can get in touch with either of them on the Lonestar Randonneur discussion group at
http://groups-beta.google.com/group/Talk2LSR, or shoot me a PM and I'll give you their email address. What StephenH says about these rides maybe not being the shortest or flastest is true, but I will say that I've ridden lots of routes organized by both of these guys and their routes are sweet! Expect low traffic and good pavement. Also expect to get recruited into the Rando crowd. But if you're interested in a ride of this distance you should be getting into Rando anyway. Best time $20 a year can buy!
On your question about the 2010 WW Project Soldier Ride: This year is a little different, in that they are starting in San Antone and heading toward Dallas. There are a few of us here that have gone the last 2 years, and we all had a GREAT time. We get to ride our bikes and support our heros! What more could you ask for?
Steve