Canadian PR & Citizen are treated differently for entering USA from Canada.
Citizens of Canada do not require a Visa-only for visits (but they cannot work in USA without a Work Permit), however PR do require Visa for entry, whether it is work or visit does not matter. Duration of stay depends on the type of Visa you have. B1/B2 usually get 6 months of validity to stay. Work Permit rules are the same as for anyone else having a H1 or J1 Visa.