I'd say P&G for this vehicle at
highway speeds isn't worthwhile anyway.
Just a hunch, but I bet the transmission losses under accel (and the inability to control for load) combined with the aero losses during the coast at higher speeds would make it an awful lot of work for little or no gain and arguably more wear. I could be wrong - haven't tried it with the
SG in this type of vehicle.
Lower speed engine off coasting is another issue. I've done some in my brother's Chrysler minivan (same as yours, but not sure if his V6 is the same displacement as yours) - approaching stop signs, that kind of thing. You probably already know the steering is MASSIVELY heavy on the van without assist. Brakes are A-OK for one or 2 reserve-assisted applications, of course.
Also, you probably already know you can get to neutral with a palm-forward "push" of the lever, right? (Pushing away and slightly up.) No need to pull the lever to get to N. The "push" movement minimizes the risk of selecting R or P by accident.