With 3500lbs of pin weight, no way can a SRW of anything tow that and stay within the trucks ratings.
It isn't all about what a truck can tow, it is also about what a truck can HAUL. 2 different things.
Anything over 35' needs a DRW to we within the tow ratings of the truck.
Can a 2500/F250 do it? Sure.
Do you see lots and lots of people do it? Sure.
Does it make it right? Nope.
If you are one of those folks looking for someone to say "I've been towing a 41' Hauler with 3 slides for years with my F250 and airbags, I don't have any issues." Then you will get plenty of folks saying you will be ok.
If you want to actually talk weights and reality, that is a different story.
If you want to talk reality, let me know and I can post up some CAT scale tickets of my setup and you can judge for your self.