Ryan, as a rebuilder of turbos I'd like you to drive hard and shut 'er down right quick. As a fellow BBoarder I'll dispense kinder advice.

As soon as you force hot fresh exhaust through the turbine, you're heating the turbine housing more than a NA exhaust manifold. Even idling for 5 min. will not bring the temps in the castings down to a non-coking temp. Light and gentle throttle application for the last few miles of your trip, frequent oil changes (1500-2000 mi) on good petroleum based oil, this includes many "blended" off-the-shelf synthetics, or a good quality synthetic oil, Amsoil, Redline, Lubro-Moly, Royal Purple, changed every 10,000-15,000 with filter changes every 2000, and a modest 30 to 90 seconds of cool down idling time in the driveway will preserve your turbo for a long time. Remember, cooling down a super hot turbo by feeding it hot coolant, hot oil, and hot exhaust gas is not a great way to drop temps quickly. The most benefit is realised by protecting it from inevitable heat-sinking with a really good oil maintenace program.

Our family turbo saw 60,000mi of severe abuse(removed becuse of ongoing hp project) and very short cool downs. It did get only the best in oils and frequent changes. When I took it apart, it had only the slightest of coke build up at the turbine-end seal. There was absolutely no coke at any of the bearing surfaces.