I towed a 4800lb fifth wheel from Ohio to San Antonio with an 07 F150 with the 4.6 in it with no problems more than once.
I doubt you will have any problems at all.
Unless things have changed you only need them in bedrooms, within 15-20ft outside of bedrooms which usually means one in the hall and one on every floor. Im pretty sure you do not need them in every room.
Who told you this anyway?