Softening F350 suspension

I have a 99 F350 with stock suspension that I use to tow my car to shows with.I what to know is there any to soften the suspension on it because when I am not towing it beats me up pretty good when I am not on the interstate can I put different shocks or spring on it and soften it up some any suggestion, Bagging it is not and option right know,

shoulda got a 250 then

pull some springs and replace them with air bags. that way you still have the towing cap and the softness of bags.

tow a really heavy ass load worked on my fx4 ranger lol