I have worked on two projects in which the builders used detached houses that came with the purchase of the land, as the construction jobsite office in lieu of a temporary trailer.
This approach saved the builders the expense of providing a temporary office trailer, but in these two projects these fixed-in-place houses became farther and farther away from the construction in-progress as each new phase of tract houses moved farther away from the first phase closest to the house office.
These growing distances resulted in a forced and unnatural isolation between the field office and the construction, especially when the distance became too great to cover on foot.
A temporary office trailer allows the trailer to be moved so that the construction office is not more than a few hundred feet from the actual construction in-progress.