IR1 PR reside in Canada want to apply for re-entry permit.
I wouldn't do that if I were you, for if you do, then you're admitting to have already abandoned your permanent residence in the US.
Behar Intl. Counsel 619.234.5962 Kindly be advised that the answer above is only general in nature cannot be construed as legal advice, given that not enough facts are known. It is your responsibility to retain a lawyer to analyze the facts specific to your particular situation in order to give you specific advice. Specific answers will require cognizance of all pertinent facts about your case. Any answers offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship.
I agree with Mr. Behar. You should use a US address.
You should use the address to which you will return after your extended trip abroad. I recommend that you consult with an immigration attorney to discuss this matter further.