I tried using my smartphone as my audiobook player, GPS, and phone on a long trip last year. A dashtop GPS receiver is far easier to read and use than the phone. In addition, you won't miss any turns when your daughter calls to chat for a half hour.
I have heard good things about using an iPad with a GPS app, but it ends up costing about the same as a "regular" GPS unit.
Mike Butts
DW+DD+DS+Poodles
2017 Forest River Forester 3011DS (first MH!)
Previously 1999 Coleman Santa Fe pop-up, 2007 Kodiak 23SS hybrid, 2013 Sunset Trail 29SS travel trailer