If your product itself is the delivery ‘service’ why would you want it to be associated with a warehouse?

The routes, work on the product lines on a delivery order. But since you would have only 1 line, all that you would want to track is the steps. The functionality of backorder and returns wouldn’t be of consideration here.

My suggestion would be to define as a service and create a task for the relevant store. Define each store as a project. (This would be the equivalent to a WH) 

For each Project define the stages to mirror the routes of WH. Furthermore you also have the ability to restrict access at project level, same as you would have in a WH.

Am not sure if I may have understood completely your user case here.