Installed rear air bags prior to towing 16,000# 5er on our 2011 F-350 SRW 4x4. Now have Palomino 2902 and only need to run 30# air in air bags to keep unit level. With this amount of air the ride is comfortable and the body roll is noticeable only on severely "crowned' roads.
Your set up should be fine to handle your new TC. As previously mentioned, air bags would help you get back to level. I purchased Firestone air bags on E-bay for around $385 and installed them myself in about 2 1/2 hours. Biggest problem I encountered with the install was removing the "rusted on" rubber spring bumpers mounted where air bags needed to go. Your set up may be different and less troublesome.
Also we are thinking about returning to Alaska in 2017. Maybe we will share a cup of coffee while exploring this beautiful and wild country...
Good luck and safe travels.