How come you have open work permit? Is it through your spouse's PR in progress /workpermit ?
You need valid visa and valid and relevant reason to enter the country for using your visa. I assume you require visa for your passport https://www.cic.gc.ca/english/visit/visas.asp. Do you have/need visa?
I dont know much about entering Canada using work permit.
I assume that Work permit is for people who are working. So call the cbsa and they will tell you if you can enter.
Job offer not needed since it is a OPEN work permit (not tied to a specific employer). I hope your W1 visa on your passport is still valid. You can enter Canada without any issues.