I just wanted to share a navigation tip.  I just discovered you can take three rubber bands, put your offline gps navigation app in landscape mode, and attach the phone to your rear view mirror using the rubber bands, which are completely sturdy enough to hold an average android to a rear view mirror.  This avoids having to lug around a phone holder, and is especially useful in places with only manual transmission cars and allows you to drink a bottle of Coke Light while all the while enjoying the driving experience using two hands on the wheel instead of holding the phone in one hand while trying to shift!    
   
 Also don't forget to bring a car charger because gps navigation takes a lot of battery power.  The best car charger is to just get a car charger with a small single usb output then you can use the usb cable for double use - in that many planes now have a usb port and also computer labs you can also charge the phone it, as well.