Hi mustex,
Most of the year Canada will have temperatures well above freezing. I live in one of the coldest parts of the country and freezing is a concern from the middle of October until the end of March, though of course that varies. I use my RV year round, and simply winterize after any trip.
You will need to look for a so called "four seasons" RV that has a heated "basement". Read the entire thread for lots of suggestions. Since you will be full timing, it make be good to add some modifications to any RV to keep it comfy.
Often there is a horizontal run for both grey and black water tanks.
Here is a link where you can look up the weather "history" of the locations you plan on going to:
weather underground