The PRCs come by regular mail to the address u provided upon landing. No signatures, no acknowledgement etc is required. It just gets dropped in the addresses' mail box. Which means anyone having the key to that box can access it.
Thus, u can return the very same day of landing, after u r done with the landing procedure. U don't need to remain in Canada for any no. of days, except for the 730days in a 5yr period for maintaining your PR status.
The PRC can be received by your "collector" @ the address provided & s/he can further mail/courier to u anywhere in the world. There's a risk though, of sending it overseas (lost in transit), but ppl do it all the time.
Qorax