I consider a good mat essential to our set up. Without it the camper will slide around in the bed. The mat adds friction to keep things in place. Without it the camper can actually slide around in the bed. NOT good.
Maker sure the camper has swing out jack brackets on the front to clear the dually fenders. These can be added to the camper if they aren't there but you will not be able to load the camper without them.
The other mod to the truck/camper will be to make sure you have the correct wiring harness. I think Lance has their own plug style into the camper. Make sure you get that cord with the camper and make sure it's long enough to reach the 7 pin trailer plug at the back bumper. Many of us install a new 7 pin plug in the bed near the front. In any case you can buy a 7 pin extension cord if you need the added length to get to the back of the truck from the front of the camper.
As others have mentioned you may want to budget for installing suspension upgrades but I would load the camper first and see if the truck sits level first and how much if any the overload springs engage. Could be that your ford dually has enough suspension stock. I would however consider adding a sway bar and possible better/new shocks such as Bilstiens.