In the height of the afternoon, do not push too hard, try to get all or most of your "hard" riding done early in the moring when you are "fresh". Make sure you stay hydrated and get some recommendations from the long distance riders out there to be sure. Do not ride impaired...if you are tired, been riding hard in high heat, be sure to allow extra time to rest and hydrate. Riding with GPS and other riders (w/ intercom) is nice, but not necessary. Calculate your trip based on 40-45mph (sorry Rob) but this is realistic from a rest stop/fueling and foot stops and expected mileage coverage. I say this because you are not trying to run a marathon, and riding fast and out of your comfort zone is the last thing you should want or need.