Is the factory "lift" on the Offroad simply from new coils? If so, the 5" lift kit will not lift you any farther than a standard Ram since the coils are replaced, unless there is a kit specific to the Offroad.
I doubt that you will fit 37's. My 3"/3" combo barely clears my 35" Swampers. In fact they tear up the sheetmetal when I am really flexing it. I suppose that the 5" kit pushes the front axle forward and my problem there would go away, but in the rear, I am chewing up the front of the fenders.
Just something to think about. It may just be my truck (sagging and such after 115,000 miles and hard wheeling)