You can have factory nav installed outside of the dealership if you don't care about the cost. That's probably the cleanest solution.
I put in a double-DIN Kenwood DNX570HD that I found factory refurbed for around $500. Has pretty good Garmin nav + lifetime traffic and starts up quick enough to activate the rear-view camera by the time I put it in reverse. This is important and often overlooked. You don't want to sit there waiting for it to go through a long boot up sequence just so you can back up.
There are way better units out there like the Pioneer AVIC line as mentioned above if you want to spend more. There are things I don't like about it (small screen being #1, but I wanted a volume knob and you can't have everything with double-DIN), but it's relatively inexpensive and I don't have to have extra things floating around on my dash so I'm happy.
2017 Escape 17B, 2012 VW Touareg