I am currently a PR within Canada. In terms of citizenship, I understand I need to be physically in Canada for 3 years out of 4. Does this mean I am not allowed to go on vacation out of the country, such as for 2 weeks with my spouse who is a canadian citizen?
It means that out of a four year period, three of those years must have been physically spent in Canada. So yes - you can certainly go on vacation provided that you don't spent more than one year out of the four years outside of Canada. Note this is expected to increase to 4 years out of 6 sometime next year.