My sister is visiting from Egypt. She will have a Canadian and American tourist visa. We will be taking the Alaska cruise. My husband and I (US citizens) were planning on meeting her in Vancouver where she flies in to, do a bit of sight seeing there and then drive back to Seattle to hop on the ship. After the cruise, we were wanting to Drop her off at Vancouver to catch her flight. Can my sister go back and forth across the border multiple times by road and ship over a matter of 10 days?
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.