I can't really answer about the experience of the border because I originally came in on a work permit.
Perhaps these threads might help?
http://www.canadavisa.com/canada-immigration-discussion-board/crossing-canadian-border-with-wife-from-us-t22091.0.html
http://www.canadavisa.com/canada-immigration-discussion-board/what-is-dual-intent-t13358.0.html
And yes, I think having proof of ties to the U.S. would help demonstrate that you are visiting (bank accounts in U.S, if you have a lease for an apt, a letter from your employer if you are returning there to work, return travel ticket, etc.) If you are visiting, but only have few ties to the U.S., it might be more difficult, so I would think things like financial support would be more closely looked at. Are you and your spouse going to be traveling together?
I would not travel with too many belongings, just a "trip's worth." Other things: proof of funds to support the non-working spouse, the receipts of payment for PR application, marriage certificate, and if you come after submitting the application, I would bring confirmation of that (confirmation of courier deliver, sponsorship approval, whatever you have).