We just finished our spring break trip - spent a glorious week in Fort Wilderness at Disney in Florida. First trip with our new 3750FL - it was fantastic.
For trip routing, I used the Garmin mapping program MapSource and set waypoints for all the rest areas and expected fuel stops as my family tends to require frequent rest area stops.
I programmed a waypoint for just prior to the off ramp for the rest area or fuel station. (First effort, I programmed the rest area itself and if we did not stop, it wanted to reroute us back to it.) The GPS displays how far to the next turn or the next waypoint - so we always knew how far it was until the next rest stop. I was the hero - boy, that doesn't happen often.