Work backwards from the credential rather than from the start date. Where an evaluation or a certified translation is needed, allow weeks before anything else is scheduled.
The credential sets the clock
A port-of-entry application is presented and decided at the time of application. The preparation timeline sits earlier. A degree issued outside Canada, Mexico or the United States needs a reliable credential evaluation, and a non-English record needs a certified English translation. An employer letter may need revision before the duties read as professional planning rather than technical work, and if the offer changes during negotiation the letter has to be rewritten again. Where the employer files Form I-129 instead, add the current processing time and remember that a decision can never be assumed in advance. A sensible order is credential first, letter second, travel and housing last. Giving notice on a Canadian job before the credential question is settled creates avoidable risk.
Hypothetical example: a shoreline-zoning planner is expected to begin after a council adopts a seasonal plan. The first review should create a reverse calendar from the genuine start date, showing when the employer letter, credentials, passport, and any licence evidence will be final. A signed offer and the credential issuer's record settle the milestones. Gather documents before notice is given at the current job, then choose between inspection-based processing and an employer petition based on the business need for certainty. The usual mistake is treating a verbal start date as fixed while the supporting description is still changing.