First confirm the proposed U.S. activity and admission process. Travel distance affects logistics; it does not determine when professional work is authorized.
Plan the practical logistics around the same legal steps
Obtain the intended U.S. work period and recipient’s availability before arranging travel. Confirm current procedures for the actual port or preclearance location, and leave time to resolve differences between employer and client records. A Canadian commuting pattern is separate from the U.S. admission and work-start plan.
If the file is not ready, returning to Canada and completing preparation there is a legitimate outcome rather than a setback, particularly for a Canadian citizen who may later seek TN admission at a port of entry. A Canadian citizen can apply at a port of entry on the day of travel, but redrafting the offer, obtaining transcripts and restructuring a contractor arrangement into employment are what consume the calendar. If a start date is already fixed, raise that constraint with counsel immediately so the sequence can be planned around it, rather than assuming the letter can be fixed in transit.