Alright, so I can use Google Maps to plan out routes for the bicycle.. and there's an option to 'send these directions to your phone'. Is there an option for any cycling GPS unit to have that same kind of navigation and display from google to it?

If not, and I'm expecting not.. what is the best cell phone to bicycle mount holder out there? I have a Galaxy S4 phone but I am using an aftermarket battery that gives me more battery life (since I figure I will also need 7-8 hrs of gps / navigation).

So, advise on a possible GPS cycling computer OR more probably, advise on a cell phone holder mount?