-2- IF you or your hu*****and has income in U.S., you can file canadian tax first, and then file u.s. tax. There will be no double tax, because usually Canadian tax is higer than U.S. tax. IF you do not work and have childern, your tax in Canada will be lower, and you can also deduct your tuition against your hu*****and's income tax in Canada
-3- You can apply a B1 visa, however, to entering U.S.
IT will not impact you canadian residence....what need to do is not hide the fact that your hu*****and in U.S., but to let Canada Immigration know that, your hu*****and work in U.S. and you stay in Canada and both of you file tax in Canada, as long as you will not have lots of cross boarder record on your passport.
-4- Usually, when you driver cross back to Canada from U.S., they won't give a stamp on your passport. Also, remember it's not like China, people leaving Canada or U.S. won't have any records if they drive cross. IF you can convince Canada you just spent weekend in U.S., they will let you pass without stamp. Also, select your port of entry carefully, sometime you need to pick a more friendly port of entry to Canada.