"Also I am wondering what type of F-150 you have that only weighs 4,800#? I had my 2007 F-150 4x4 weighed with me in it and 3/4 tank of gas and it was 5,960# and just went and looked and it has a 15,000# GCWR. It list the tow rating in the book as 9,200# but according to my math my truck would only be able to handle 9,040# and be legal. So I am limited in my case to hauling trailers with 9,000# plates or less. I guess that is due to the options on my truck and the things like a bed liner, tow straps, plus some tools I carry around."
My F150 is a 2001 4x4 shortbox and it is suprisingly light. You're weight makes sense though as the newer ones are more solidly built. Your GCVR is also #2000 higher than mine which fits. I'm sure your weights are right, my truck is just on the light side for an F150 and your's is on the heavy side.
As far as being limited to 9,000# plated trailers that's not how I understood it. The plate weight only means you paid the king for the privilage of placing that much burden on his roads. You could haul a 14,000# plated trailer as long as the actual weight didn't exceed your tow rating. That's how I understood him and the weight laws don't mention registered weight, as he said.
This thread has been great for me because it forced me to actually get off my butt and look into it instead of guessing what was and wasn't legal in Indiana. I get more out of the time I spend on TBN than anything else I do on the internet, that's for sure!