Depending on where you all call home, I'd consider doing what I did, and getting it sprayed with a Line-X or RhinoLiner coating. Same stuff they spray in the steel bed of the older trucks (many are now like the Ridgeline in some sort of composite). It costs very little and will never rust. Just don't spray the tongue piece or it'll never slide in....lol.
If I ever added running boards, I'd spray those as well. Doesn't cost that much, provides grip, and certainly stalls the aging process. Just something to consider if you live north of the Mason/Dixon and the answer to everything cold is pour more salt on the road...