It is impossibly to post transfer order without treansit location by standard NAV.
This is because shipment from one location is not receivement in other location. There are ususally different whs.employees who are responsible for only own locations. Because of that one employee onl ship item, and other onl receive it.
If you want to use simplier process, you can use Item Reclass. Journals for it. You can fill Location Code and New Location Code and post it.