since when have iphones not had gps? ive never had an iphone but always assumed they had the same A-GPS style receivers almost all smartphones have today. A-GPS is assisted gps, meaning it uses the internet to download the gps satellite locations for a faster gps fix, without internet they can still get a fix, but its a cold fix that can take up to 10 mins to aquire.
there is also a trial version for backcountry navigator if people are interested in trying it out, its good for 21 days so this trip is perfect for trying it out if you dont know if its worth the $10. i use it alot for the topo maps out in borrego.
id be interested in your gpx, danny.