Any trip during which you didn’t spend the night in the US doesn’t count as a trip outside of Canada. So can ignore all of those.
When you submit your PR Card application, you can give IRCC permission to contact CBSA to get your entry information, so they will have a record.
But you should do you best to provide as much information about your trips as possible. If you have made purchases in the US, maybe you can use your credit card statements to figure out when you were there.