A Canadian citizen can apply at a port of entry on the day of travel with a complete file, so ten weeks is ample if the documents exist. The constraint is assembling employer letters for three management years, which should start now rather than the week before departure.
The border is fast; the paperwork is not
The port-of-entry process gives Canadian TN applicants a decision at the time of application, which suits a seasonal start date. The risk is not the process but the file. Hypothetical example: the applicant's management years span the Harrison Hot Springs resort and a property in another province that has since changed owners; obtaining a letter from the earlier property's former general manager could take weeks.
Start the letters immediately, obtain the diploma transcript from the college, and have the lodge issue its offer letter with duties, pay, a period not exceeding three years and an ownership statement. If any document may be delayed, consider whether the lodge should file Form I-129 with premium processing instead, which yields a written approval to present at the border and removes the exposure of a first-time port-of-entry refusal. Either way, the applicant should not resign from her current position until the file is complete and the route is chosen.