BCKev said:For Question 12, only the addresses where they lived are needed:
"Question 12 Indicate the residential addresses where you have lived since your 18th birthday or the past 10 years, whichever is most recent, complete with the postal code. Do not use P.O. box addresses."
http://www.cic.gc.ca/english/information/applications/guides/5772ETOC.asp#completeApplication
Question 8: I am not sure if it is necessary to mention a short visit to the US. It may not be necessary, but won't hurt to indicate travelling in the US. My impression is that this question is primarily intended to be about where people lived and worked, not where they had short vacations.
Hopefully someone else could share some wisdom on this question.
Thank you very much for your answers! Much appreciated!!!