Good call on dropping the truck down to a quality 2.5" lift with a slide in camper. This should dramatically improve your emergency handling. An E-rated 80 psi tire with a super high load capacity rules too. The last thing you want is a blowout with a cabover. Ask me how I know. Almost lost my life when my D-rated(3305# @ 65 psi) Bridgestone tire blewout on I-15. $3300 damage in seconds and me and the truck narrowly avoided going over the edge of a 100' dropoff. Tire had plenty of load capacity,just mushy sidewalls with the D rating. Toyo E-rated M-55's solved the problem.
With all that weight,I can't stress enough how a custom valved reservoir shock and a Hellwig Big Wig swaybar will further enhance the handling. All it takes is money and lots of it.