The warehouses themselves wouldn't have any machinery wired up or anything, but you can bank on there being some computers for storing and transferring inventory information. They'd probably be wireless and, in the possibility that all of the warehouses are owned by the same company (who's to say,) they might even be in a WAN together with the other warehouse computers.

Short answer: WANs yes, Hosts no. You'll probably have to leave the house for this one (though I won't tell you how to play your character.) These will be older computers (probably from the dawn of wireless) and only used for business reasons, so there's no reason to assume they would be connected to anything other than each other.

If there's anything connected to the Matrix proper in the buildings, it's probably something like a commlink or something else brought in by a worker (thus public grid.) Nothing business-related would be open access.