looking to buy my first gps. for prospecting, hiking,canyons, tree cover etc.my eyes are not what they used to be. any recomendations on units with large screens? i was looking at the garmin e trex h c x. looked like it had everything i would need & more but the 1.3 x1.7 is a very small screen. am i stuck with a hand held or is there a car unit that is as good that is also portable & waterproof. help!