As everybody has already pointed out, the real problem is not with the set piece but with the Technical design and implementation. the scenic design is not the problem. Many shows have large scenic pieces that would be impossible to tour, but when they DO tour, the way they are built is redesigned. I once toured Bye, Bye
Birdie and everything, E V E R Y T H I N G, fit into 30" x 48" x 60" aircraft cargo containers, (as you probably guessed, a USO show).
Now for the
unit you are stuck with. IIUC, the show surface is adhered to a hard backing, can't be peeled off without damage. One possibility, carefully score the back along the 12' axis just on the sides of the Decal until the
unit will fold to the
face in a 3 fold. It won't fold
flat due to the framing but the folds from the side to the decal to the other side would be be a size to fit through a standard door.
As suggested earlier, cut the decal off, out of the center, cut the backing piece in two and
coffin lock to
butt join or hinge to fold.
Velcro or carpet tape the decal back on at each stop.
cut the decal out and then cut the background into pieces, with the decal as a center
point. With 4 pieces the seams make a cross behind the decal. With 5 or more you have a star-burst behind the decal. Old design trick, hide by emphasis,
cover the seams as each stop with colored tape, or 1x3 painted in a contrasting color to make a raised decoration or...... Use you imagination. If the original designer is on tour, tactfully ask for his input because you are worried that you will damage the
unit in transit or have to cut it apart at the last minute to get into a
stage.
Other ways..... Think about how the
unit is framed and built. Remember straight front low angle lighting helps hide seams and joins. high angle or side light makes them stand out.
HTH.