ESTAの件も私の回答ですね。
私自身も最後に陸路で国境を越えたのがちょうど3年前で、毎回ESTAを持っていたのでESTA無しの経験はありませんが、ESTAが必要かどうかは検索すると出てきます。
Residents (PR) of Canada who are landed immigrants generally need a passport and visa to enter the United States, unless they are a citizen of a country eligible for the Visa Waiver Program (VWP). If they are a citizen of a country eligible for the VWP, they are only required to have their valid passport - coming by land or sea. If coming by air, they will need to have advance approval to travel through the Electronic System for Travel Authorization (ESTA). There is an ESTA application fee of $14. To obtain a list of countries eligible for the VWP, please reference the Department of State Web site. https://help.cbp.gov/app/answers/detail/a_id/619/kw/by%20land
とか