I agree that the size of screen on handhelds is a problem, but for brightness, my GPSMAP60C does the trick. When working on battery, the backlit screen (which has varying levels of brightness) stays off until you press a button to see the screen and turns off again after a couple of seconds. When you plug it in, though, it stays lit and is pretty visible.

As far as mounting options go, Garmin makes handlebar mounts, belt clips, suction cup/sandbag auto mounts (I use the suction cup in mine) and various other accessories for the GPSMAP60 series. Topo maps, city maps and blue charts abound are available. If you get the new Cx model, you get the expandable memory slot that takes SD cards as well.

If you can't tell, I'm happy with it! Good luck!