I was doing the same thing first with a Nexus 5 but quickly discovered that neither the battery nor gps were up for this task. Got a sigma rox 11.1 recently and for 100 bucks this thing is worth it, but it doesn’t have maps and only shows a preloaded route instead.
Ah, so no navigation, just maps. Yeah in that case a setup like this is unbeatable for the money. But it can‘t beat the guy I‘ve seen recently with a tablet sized map strapped to his bars.