R51 Towing Questions

I've recently starting towing a 3,000lb. camper trailer (400lb. tongue weight) with my R51 Pathfinder (V6, 2WD). My fist orders of business are mirror extensions and a trailer brake controller / 7-pin wiring harness installation.

Are there any other suggestions for critical upgrades I should be thinking of?

Most of my initial towing will be in fairly flat areas of the Southeast US, but I'd like to eventually do some towing / camping in the Appalachian and Rocky mountains.

Oh, and the camper trailer already has a weight distribution hitch and friction anti-sway bar installed.

Thanks for any suggestions!