Driving into Canada, Vehicle Ownership/Reg requirments.

Hello all, 1st post here....

In July of this upcoming year I plan on taking my GF, her 2 kids and myself to PEI for 1 week of vacation.

We are in the process of getting Passports for each of us, getting a notarized letter from the Father (There divorced) consenting to his children traveling into Canada, along with documentation (Prescription and Dr.'s Note) for my Gf's Daughters Epi-Pen (Allergic to Peanuts) which hopefully should easy our entry into and out of Canada.

My real question is I plan on borrowing my Mothers vehicle as it is more reliable than my GF's Mini Van, and my Truck won't accommodate all of us, so what types of documentation will I need at the Border crossing? I can have the Registration and Title to the vehicle however they will not have my name, they will have my Mothers name on them, will this be an issue?

Also, I keep reading about Financial statements and the needed proof of sufficient funds to enter into Canada? What will I and my GF need to comply with this?

Any other helpful hints to make this process go smoothly? I don't want to pay for our beach rental, drive 11 hours from Mass. to the Ferry/Border in Maine, only to be turned away because I don't have some sort of proper documentation.

Thanks.