Although not quite as heavy as an MA-550, I recently moved a crank-up
tower with a nested length of ~8.3m with a 2.something tonne Mazda flat bed
A 2.something tonne Mazda flat bed lorry is not much bigger than a US mid-sized
pick up truck - if at all.
Like the 5.5 tonne Isuzu that first moved this tower, the back is not enclosed
& the cab has a light frame immediately behind it on which the tower can
rest - no overhang to the rear... just heave it up there & lash it down.
I would be concerned about much weight up too high, but then again I don't
recall there being too many bends on I-5 between Portland & Seattle... not to
mention that the kerb weight of a typical US pick up truck is probably more
than the maximum GVW of the Mazda.
Just beware the state constabulary in the vicinity of Kelso. ;^)