Getting to/from Erewhon Station without a car

We've got a party looking to do a crossing of the the Gardens of Eden and/or Allah late this coming summer. The most reliable access is from the east via Perth Col and it would be great to have the option of doing a through trip to the West Coast finishing either down the Perth or the Wanganui. Or maybe we'd do the whole trip in reverse (i.e. west to east) and finish at Erewhon Station. We'll all be flying in from Oz so don't have our own transport, and we'd really prefer not to hire a car. Bus access on the Western side is easy to arrange so that's no problem, but is there any way to get to/from the eastern end of the route (Erewhon Station) without having our own wheels? I've been doing some web searching for some time on this but without any luck so far...