I have a couple cheap Nokia 520-521 phones ( Windows 8.1 ) that can use Nokia Here maps

How good are the Nokia maps for Thailand ? and street maps / sub sois in Bangkok ?

I was told the Nokia Here maps work better on Windows than on Android

I do not mind bringing an extra phone to use as a GPS

thanks for your ideas

Very good. (Also Here! for Android. Same Maps. ?!)

I really like the Android version of HERE, using it mostly offline in northern Thailand unless searching for a specific named business.

My only niggle with 'HERE' is it keeps running on my phone after closing, sucking battery. But since I have other apps that do the same I have a ES Task Manager set to kill them before putting the phone back in my pocket.