Thanks this topic is timely for me so here's my .02c and please don't overvalue it!!
Ive experimented using Google maps but my rub is that I want to retrace my route. I don't believe Goggle maps will track me.
So I subscribed to the Rever app on my iPhone 5 SE. I created a custom mount and this past weekend did 500+ miles in Wisconsin's upper peninsula. Tracking feature does what I wish.
Rain:
The SE is rated to survive an hour submerged. Not sure if I want to test that, nor do I really see myself continuing for long in a deluge. I think a smartphone option is workable even in the rain. Adjustments with a fingertip would require the screen be wiped dry in even a drizzle. That would frustrate.
Power: GPS apps like Rever, Google Maps et al suck battery in a big way. looking at my first ride, this past Sunday, the app and my phone lasted all of 67 of 413 miles from full charge....I have been sitting on a USB power jack for over a year- its time to install it for continuous recharge.
Mounting headaches: K75S is a challenging set up. I opted against center mounting. (I mounted, ok TIG welded a RAM phone mount on my right mirror above the throttle. I'm a righty, the hand moves at a minimum.
I'll stash the charger out of sight and thread one of these aftermarket fabric sheathed cables up the handlebar to my right mirror position mount for stealthy power....
I like the Apple 5 SE form factor, smaller works better for me in general, I can mount it to the control yolk of a 172 airplane (foreflight app), but on my K maybe a larger screen would be beneficial.
Miscellaneous ramblings,
Cheers