google is already offering caching system on android which can provide a good alternative to times when you lose data connectivity for some time period. caching works well in my case. it stores the maps of your frequently visited places right now. not sure if it would cache the maps of the routes you are defining. of course, this problem also exists in the US market so its not like they are not aware of it. and of course, their maps are way too comprehensive to be stored locally. so it's better to define your route, let the device cache the maps for that route. and you are sort of safe even if you lose connectivity on the way.