[NorthMountain]

Suggestions:

1) Get a digital camera, from Nikon or Canon or whatever, that uses AA or AAA batteries.

2) Get a GPS device, from Garmin, that uses AA or AAA batteries.

3) Don’t count on having cell reception of any sort when you’re out in the boonies.

4) Bring whatever brand of cellphone and/or tablet you like. If you follow (1) and (2) above, you won’t get burned when your cellphone/tablet battery dies.

BTDT.

[NorthMountain]

Oh, yes:

Bring extra AA or AAA batteries.

[Yosemitest]

I've been researching the GPS devices and the digital watches with altimeter and barometer.
I like the digital watches, but not the GPS watches because of short battery life.
The I-phone and the I-pad both can take an APP that is a GPS Altimeter that doesn't drain the battery near as fast, IF you use it off and on.
But if you leave the altimeter GPS function on all the time, it drains the battery pretty fast.
Research SpyGlass, and "Exact Altimeter for iPad by BitKnights"