Don't know if you can find one for 2001, but I bought factory mat for my 2017 F350 and for $150 consider it great value. My camper has steel edges with sticking screws, that I don't think I would like rubbing my bed, beside possibility of truck sliding on the bed.
Suspension modification is whole other story.
I did not worry about it till I put my camper on and turn out that at 5600 lb my camper is doing fine with factory suspension as long as I keep rear holding tanks empty.
Amazing how much 200lb of waste under camper rear can change in driving stability.