There are other documents you can use to re-enter the country.
When you return to Canada, apply for a PR card if you plan to travel outside Canada again.
Some examples of private vehicles include, but are not limited to: a car, truck, motorcycle, or recreational vehicle that you own, borrow, or rent. It is a vehicle not available for public use.
Why would I renounce my permanent resident status?
There are multiple situations in which a person might wish to renounce his or her permanent resident status including:
You only want to visit Canada and you know you have not met the residency obligations because you have been outside of Canada for a long period of time and
You don’t want to wait for a visa officer to assess whether or not you are still a permanent resident of Canada; or
You would like to apply for a temporary resident visa or an Electronic Travel Authorization (eTA); or
You would like to avoid delays at the Port of Entry.
You no longer want to live in Canada permanently. http://www.cic.gc.ca/english/information/applications/guides/5781ETOC.asp
"You may list up to four people living at the same address on one card."なんですから、1枚のDeclaration CardだけならVisitor以外って判断になるのは当然でしょう。
普通はPartBとPartCを同時に記入する事も無いでしょうし。