Buzzworthy -As Dave pointed out you have 60' of truck and trailer. You have a huge overhang with the trailer. With the trailer axle location where it is I would guess the rear corners of the trailer will move about 2/3 of what the front corners do, in the opposite direction.
With a 12' wide door you only leave yourself 1.5' on either side (with the ladder) The odds are against you never having an issue.
Sine the truck-trailer is 60', the 60' recommendation gives you a couple feet of leeway since the pin is 5' ahead of the truck's bumper, another foot or so if you use teh setback of the pin from the nose of the trailer.
Another disadvantage you have is the truck. And F-350 with an 8' bed needs a parking lot to turn around.
My vote is the 60'
Thanks, Harley-Rider and Old Crank. If you had a 14' wide door on your garage, would that cut down the 60' distance to perhaps 50" or less because of the quicker exit turn?
Since you don't have a garage to actually try this, perhaps a parking lot with cones? The potential problems I see are possibly getting into a position that you can't move the trailer without hitting something. The rear swing will be your concern.
I'm guessing the pull in part is not an issue?
The other alternative would be, and this is not something I would want to do every time I leave, would be to exit the garage until the tail is clear. If you can wiht your hitch, un pin the saddle, raise the trailer and then reposition the truck at the angle you need to get onto the street. This would just complicate things and complications can lead to damage.