Why are you organising shipping? Typically thats the buyers responsibility.
I usually do this, including building a crate, if necessary. And yes, it's largely a thankless task. But, it also expands your market, meaning higher selling price.
Haulbikes is the easiest, no crate required and they have their own dedicated, enclosed, trucks - very professional. The compromise is their timeline which can be several weeks.
If you can build a crate, a number of LTL haulers can be used and a Z50 requires a very small crate. I'd estimate 2x3x4 feet would do the job. Forward Air will probably haul a crated Z50 for around $200-250; they're a bit difficult to deal with...USPS money orders only, for payment, exact amount only, unless you open an account with them.
Uship has worked for me but, again, the bike must be properly crated and the hauler will probably be a private guy with a pickup truck and an open trailer. The drivers I've met through Uship have been real salt-of-the-Earth types, usually early retirees looking to subsidize road trips. I've always wondered about the insurance angle, though.