Iggy
Guru
Its possible to go with a touch screen and not use a mouse or keyboard. Without a touch screen, you can use a mouse with a pop-up (on screen) keyboard it will work fine, just slower when you want to enter or route name or similar.
We have 2 time zero systems running on adjacent screens, and a single track-ball mouse that covers both screens, much like you would do on a dual-monitor desk workstation. I found a small keyboard that will work with any of up to 3 outputs with the push of a selector button.
You can certainly navigate with a laptop or ipad. Its personal preference since an integrated system is a little more expensive and more work to install. Up to you to know if you prefer hidden cables, secure PC mounting, large monitors etc. enough to justify the extra setup time and cost.
As mentioned, I am using a touch screen laptop and works very well. More so with no mouse and the keyboard folded back bringing the screen more forward. I use a rubber mat that holds the laptop in place in rough seas.