This is super easy, but not necessarily cheap. You'd have to get a wrecker, pick it up, and set it on a roadworthy trailer. Sure, you can get a tire put on it to get it out of the road, but it's still not legal to tow down the road. To make it legal, you are going to need at least 2 good tires, working brakes, and working lights. If you don't get to at least the appearance of legal, you'll likely never make it across several states with out getting put out-of-service, and then you are right back to square one.
I wonder what happened to the other stuff the shipper had on the trailer? The shipper was a idiot for thinking it was even a remotely good idea to pull the trailer like that empty across the country, much less with cargo loaded on it. Very illegal in the eyes of the law. There may be legal actions you can take against U-Ship and/or the trucker. Does the "trucking company" have a DOT number? If so, please post the DOT number, if you have it.
If nothing else good comes from this thread, let it be a lesson to be very careful with U-Ship. Personally, I would never use them, but people do sometimes get good service out of them. Sure, there are shippers out there that will rip you off with high prices, but you often get what you pay for with low shipping cost.