David's ideas of using the halyards is a good idea, but only for motoring with the rig still up. Don't dare pull up sail with only rope for stays! The parted shroud will have to be compensated-for; greater than the concern for the top of the mast whipping about is that for the middle section of it pumping, especially under power. The lower shrouds are doing more work than the cap shrouds in this situation. And everything under power is yank-yank-yank, not easy steady pressure like under sail. So the likelihood for rigging (jury-rig) failure is higher, and the failure mode less easy to recover from.
Roland has a good point about removing the boom. Less weight and stuff to whip about = better in this case. Save it below for if you need to jury-rig for any sail up (re: David's point about seeing no one en route).
What David said about carting the mast on board on horses is what I meant about taking it with you. Any readers of Cruising Outpost will recall the story of Jessica and Kate doing the Great Loop last year. Like others they motored in part with the spar down, but they eventually sent it on ahead via truck to meet them in Mobile. But a sailboat with no mast in it is essentially a really inefficient motorboat; and I'd hate trusting in the engine alone (part of why I am a sailor and not a stinkpotter).
You might consider using an internal pole-lift as a port lower shroud. Also, as I originally thought, you could cable-clamp any short length of cable, or a fitting to which to attach rope, to the remnant of the parted shroud and belay it, perhaps farther forward or aft, to the toe rail. Don't merely lash it, for the rope will chafe through due to the sharp edges of the toerail holes. This is a good application for a long-D shackle, with a big pin diameter, such as 3/8", the better to alleviate movement and chipping of the toerail.
As a truck driver you may be able to strike a deal with someone having a hydraulic-lift trailer. These sell, used, for about $15,000 (new about $100,000, the more because, having one, you de facto are in the boat-moving business) but you may be able to lease one for a very short period, especially if you have the OO's insurance to cover it. Your BoatUS should take care of the boat itself and your liability for towing it.
At the risk of contracting analysis paralysis, check out all the options before sustaining regret.
'The guy who said, "Don't put all your eggs in one basket" was a fool. Put all your eggs in one basket-- and then, watch that basket!' --Mark Twain.