I run a 3500 Mega Cab SRW Limited (Heavy Extras, Less Payload) and a Montana HC 305RL.
The setup is as well with the B&W Hitch but the Turnover Ball setup.
Its also set as far back as possible and I have no clearing issues with the cab.
But I always watch it as it seems sooo close from the driver seat, but it always clears though.
Only issue with the Mega Cab I think is the Payload for SRW's.
If you want to stay inside the legal limits and of your standard tires you have to watch how and where you load.
I have 2 adults, 1 Golden Retriever, a 3500w Generator, DEF, Gas in the truck.
Attached is the Scale result loaded up for a 3 week cross country trip.
BUT I LOVE the Mega Cab. Its the best Dog Taxi ever