The standard cab allows better weight distribution than bigger one since the front axle is closer. I cannot imagine that drag will be much different since the same square footage is still being pushed through the air.
The lift will present some issues:
1. Higher center of gravity creates more leverage which results in more sway
2. Some suspension lifts have lower rated springs for more articulation
3. Jacks may not a raise camper high enough to clear a lifted bed (as mentioned)
4. With a tall camper plus lifted truck, you will have more overhead obstacles
