Sorry, I was thinking about the original posters comment about pulling a 3,000 lb trailer with his F150 and you mentioned the slack weight laws.
My post was not meant to reflect on your comments as much as point out to the original poster that he might be technically over weight, if he's using a private tag with a 3,000 lb trailer.
You're right, we have to use our heads about towing. I seen daddy pull loads where he has ran stop signs on downhill grades because he couldn't get stopped.