I don't think the air suspension coming out in the 2500s yet. It's in this model year but I haven't seen/heard of a truck actually hitting a lot with them.
I have the same truck and a similar situation to the OP. I'm hoping to hook up and tow this weekend and will report back. With my tongue weight and stuff in the bed I'm guessing I'll put 1300-1500 in the bed.
I had airbags on my old 2500 and didn't absolutely need them but they were nice to have (the occasional load or gravel, sheet rock, etc.).
I just picked up my truck new last Friday and was in a shop getting nerf bars installed Monday and asked about air bags. There are no aftermarket ones available yet but the guy said it shouldn't take long. Basically, someone just has to engineer and design some to fit the rear coils in the new trucks. One of the mainstream aftermarket manufacturers should have them soon.