My advice would be:
- consider what having to get a 7-year loan means - to me it would mean I can't really afford this truck
- if you want to buy anyway, arrive at dealer with alternate financing as a plan B. In the US, that would be your bank or a Credit Union - Canada I don't know
- do not negotiate based on monthly payment, but on cost of vehicle and warranty. From your post I can't tell how much the dealer wants for the warranty.
- for the warranty, also arrive with plan B in your back pocket. Find an online warranty company and see what the going rates are in Canada. As a reference, on my Limited, my dealer wanted $2000 more than what I had priced out online. They make serious money on the warranty if you just pay what they charge because it's rolled into the financing.
- finally - you may have your heart set on this truck, especially in today's crazy market. Ignore that as much as you can and be prepared to just walk away.