Potatoes are not illegal in Canada, but bringing them across the border is.
There really is no "best" brand of box hash browns. They are all working from the same dried potatoes so it's more about how much you want to pay than it is about quality.
I used to buy the "higher-end" hash browns until I tried some "lower-end" ones and found no difference in taste. Now I go to the bulk foods section of the grocery store, buy a gallon-sized box (which is never a name-brand), and I am set for several trips.
If you want to fancy them up at all, you can add dried onion (and they always need a little more onion if Old-Salt's in your group

) and/or dried bell peppers.
I like to start the potatoes rehydrating in cold water as soon as I crack into the food pack in the AM. Generally by the time I'm ready to start cooking, the potatoes are rehydrated. Then I pour off the water, add the butter, and start frying them up. This method makes a very serviceable hash brown. It's not like fresh, but it's good.
The box will also give you a method where you rehydrate and cook all at once. Don't even *think* about it. You don't want to go there.