I agree with Dan and Scott, But...when you pay the seller and receive the title, it is YOUR car. Make sure you have it fully insured at that point and that your insurance company is aware of how it is being stored, where, and for how long prior to shipment to you.
Generally the seller will keep it in a secured, covered location for X number of weeks for you, then charge you for storage if it goes beyond that. They will also be there when the transport company loads the vehicle. If it is going on a multi vehicle transport that won't fit in the seller's neighborhood, the seller will generally bring it to a location that works for the carrier. The seller wants the deal to work and for you to be happy. To have him not participate in the process of getting the car to you would be unlikely.
I shipped one car to a buyer that was picked up next day. They came with a huge pickup and a 2 car enclosed carrier. They took the car to their marshalling location in Seattle where they put together loads that made sense from a routing standpoint. Obviously they had the volume to do this and worked with many actual carriers. BTW you will virtually never make the transport deal directly with the transport company or the truck owner. It's mostly done through brokers.
