Be very careful on what you tell Canadian immigration authorities, Vinyl. Without any paperwork, your intent must be solely to visit (max. 6 months). However, if you should up with a US passport stamped at a Canadian Consulate in the US with a Canadian Immigration Visa, then you must tell them that your intent is to immigrate.
Once you are in Canada, correct ... you can adjust your status from visitor to resident, by filling out the paperwork, provided you have the proper sponsorship. If you were born in Canada or had a Canadian parent, you will not have a problem and in this case, you might even be able to get your Canadian Citizenship pretty quick. Not sure about the grandfather clause thou. Another relative may also be able to sponsor you. If you have no relatives and a friend wants to hire you for work, that may be another way to obtain sponsorship. There are many options, just visit a Canadian Consulate nearby before leaving to find out your options.
So you have two options. You may apply at you local consulate for a Canadian Immigration Visa and get on a waiting list. Beleive it or not, yes there are many Americans who move to Canada. Option two would be to drive to Canada and then fill out the paperwork and apply from within. You must remember to submit your paperwork within 6 months of arriving in Canada. Don't forget to ask Canadian Immigration to stamp your passport before you drive across the border. Many times they don't stamp the passport and this may cause problems for you later on. It is the only way to prove that you've submitted your paperwork within 6 months of entering Canada as a visitor. Remember, if you choose option two, do not tell Canadian Immigration that your intent is to stay. As an American Citizen, you have legal status in Canada as a visitor for 6 months.