Welcome to the forum and congrats on the new ride!
Some people don't like the liner, because if you don't pull it out regularly and give the tub a clean, it can cause rust by trapping moisture and dirt beneath it. For a similar price, you can get a spray-on Rhino liner that is tough as nails and nowhere near as slippery as the plastic liner.
As for canopies, there are plenty to choose from. Mine's a SnugTop or something like that, Nissan supplied it with the vehicle. I'm quite happy with it, the lift-up windows all around are nice because if it's sprinkling (rain) I can stand sort of under them while I get stuff out, and I have full access to the length of the area that a sliding window wouldn't give me. I don't recommend the $4,500 cost that mine came with, there must be some that are just as good without the Harrods price tag.