Haven't bought the boat yet, but the single garage door opening to my
triple garage is 105" wide, the boat I want is 102" wide. 1-1/2"
doesn't seem like much leeway when backing a 1-1/2 ton dual axle
boat/trailer in. Or is it?

It is a triple garage, but only the single door side is deep enough.
Is it possible to put her in diagonally through the double door with
the stern in the single side, then swing te tongue around in terms of
keeping the stern from swinging way over to the double side and with
the double axle situation?

I could attach it to a tongue on my more maneuverable 18 HP Honda
tractor mower, unsure if it has the strength and weight to accomplish
it - would trying it be worthwhile, or do I risk looking like
something out of a Laurel and Hardy short?

Thanks for any advice.