I agree that it's going to be really tight. I'm always surprised by how long it takes to move from place to place. It doesn't seem like it when you're in the midst of the move but then I check my watch and am surprised by how much time has elapsed!
I second the notion of showing up at you ADR at least 15 mins early just in case they're able to seat you early. There's nothing worse then being rushed during a meal to get to something else.
It may sound silly but if possible I would practice the drive between the Contemporary and DHS so that you can make the best of the time you have to make it in time for RD.