Thanks all for the replies.
I don't have 4 miles, but I do have a 500 foot paved driveway that is very steep in spots and one car wide. I need to bring it up top and swing the truck and trailer around. It levels out at the top, but not enough to prevent me from having to maneuver with the trailer on a fairly level spot but with the truck on a steep decline. To make things more interesting the trailer will be parked where I have asphalt millings (a hair better than gravel). I worry about traction so I'm going to try to keep the truck on the pavement as much as possible when getting the trailer in its spot.
I was goofing around with the 2LOW kit today and it works as designed. I have less traction when backing in 2LOW vs. 2HI for whatever reason. I brought the truck down a really steep part of the asphalt millings and it would back itself out in 2WD but with the 2LOW engaged it just dug itself a hole with the left rear tire. I'm not too concerned because I'd never bring anything but the 4WD down there but it's just an observation.
I've over analyzed this situation to death but I think I'm good. I'm bringing the trailer up here on Saturday so wish me luck...