Just a note on 'ride'.
The E450 had always been noisy and a bit rough on the road, so 2 years ago I replaced the shocks with Bilsteins. It helped but not a cure.
I replaced my tires last year and found that apparently the tires had hardened over the years. I even did the cheap shot on the new tires (Cooper Tires), I went with the US made, and they were a bit less expensive.
The following trip was amazingly more comfortable. (Old tires were Michelin with very few miles on them, but they were starting to 'check' on the side walls.)
Very good advice on the TPs, to not use more than you need to carry the load..... but watch TP on your duals (they must NOT touch or they heat up). If they touch they become 'will pops', as opposed to 'May pops'.