Bring a large pot of salted water to a boil. Add pasta and cook until al dente, about 9 minutes. Drain.
Meanwhile, heat cream in a large skillet.
Add cream cheese and salt and stir until cheese is melted.
Add cheddar and American cheeses and stir until melted.
Add cooked pasta and stir to coat well.
Transfer to a container lined with wax paper. Use a container that is small enough that your mac-and-cheese ends up being at least 1" thick (thicker is better here).
Place in the fridge and refrigerate at least an hour. You can also place it into the freezer. You want the mac-and-cheese to set up so it can be sliced.
Fire up your grill for direct cooking.
Carefully remove the mac-and-cheese from the container and slice thick.
Transfer to a grill over high heat and grill for just a minute per side, long enough to get grill marks and a bit of a crunch. Do not play with the mac-and-cheese while it's on the grill or it will crumble. Be careful flipping it. If you lose some, you lose some.
Transfer to a plate and drizzle with plenty of the Buffalo wing sauce.