T.R., I have a 2016 F350 and a 2004 Lance 845. I also had cab clearance issues so we lay 3 2×6 boards flat in the bed before loading the camper. It squeaks a bit, but gives good clearance.
Since my camper is under 3000# wet, I went with the CR Brophy Machine Works HSSF Brophy Black Finish Heavy Duty Tie Downs ($140 on Amazon). These have worked well so far.
I haven’t needed any suspension mods yet, but may add airbags once I start towing my bay boat.
I hope this helps. Good luck with your rig.
2016 Ford F350 SRW
2004 Lance 845