Thank you for your prompt reply. Unfortunately, while we were aware of the three dots in the sale order line (a nice feature) and that route would appear there as a boolean, route was not among the available options in our implementation as configured (we had only "Description," "Lead Time," "Taxes," and "Disc.%"). We do have the Drop Shipping module installed, as well as these apps: CRM, Calendar, Contacts, Discuss, Inventory, Invoicing, Purchase, and Sales. With the exception of the snailmail_account module, all of our installed modules are versions 13.0.1.* or higher.
After receiving your kind answer, we tested various fixes and found that by selecting two additional options under Inventory > Configuration > Settings, namely "Storage Locations" and "Multi-Step Routes" in the Warehousing section, "route" would then appear under the three dots.
Thank you, again, for your help--much appreciated.