Your residency status has nothing to do with your PR card. Nothing. Your PR card expiring does not invalidate your residency status. You will remain a resident for as long as you choose to or for as long as your status is not revoked.
You do not have to renew your PR card inorder to meet RO. You can live inside Canada and complete your days...meet RO...and then apply for a renewal PR card.
For as to how you will enter Canada....you can use the same PR card...even though it is expired. You can apply for PRTD....less chances of getting that through. But there is one more thing you can do.
Fly to tglhe USA...cross the land border with Canada...enter with tour COPR. There are very little chances of getting reported.
Once you ejter through land border...you can remain insidr Canada for as long as you need to...to meet RO...and then apply for a renewal PR card.
I am out of a Canada for a Canadian job. The Problem is if i apply for PR now while i am away, I meet the residency requirement. But I will loose the residency requirement in a month, when my PR card is also expired. in this case it is probable that i be rejected for PRTD.