Upvote:2
You mention in a comment that "It's a multiple entry visa." Assuming you mean the Canadian visa is the multiple-entry one, then what you're proposing is OK. She will arrive in Vancouver, you will drive her to the US (her only entry to that country), and then by some unspecified means she will return to Vancouver (her second entry to Canada).
You mentioned going across the border by ship too. If it's an Alaska cruise leaving from Seattle, will the ship actually make port in Canada? If it does, you may want to make sure that both visas permit multiple entry.