What Happens if Your GPS Goes Out?

My Buddy and I Have an iPhone and Samsung Galaxy S3 Respectively
We Both Have the GPS But My iPhone is on Virgin Mobile and His Samsung Galaxy is on
T-Mobile Prepaid

We're Getting Ready to Drive Across the Country From Delaware to Baja California
(His Family Lives there-That's Where He is From)

Well, We Don't Get The Best Reception Here, What Should Happen If We're Using the GPS App(s) on Our Phones, Will it Just Stop Working or What?

What is The Better Phone to Use for The Signal Virgin Mobile or T-Mobile?

Added (1). I'm Sorry I Meant Were Driving to San Diego to Visit His Family
Not Baja California, MX However We're Going there Eventually While There Lol

I like to keep a set of paper maps I can refer to. Even a couple of regional maps would show the major highways you will be taking most of the time. If either of you belongs to an auto club, you can probably get maps for free as part of your membership.

There are these amazing devices called "maps." They come individually and in books called "road atlases." Yhey're made of paper and have lines on them for roads, and the names of towns and cities. They never lose their signal, and they have no batteries to die on you. You can fold some of them up and store them. This is how men traveled for hundreds of years.

You are going to take interstates all the way to San Diego. Its pretty difficult to get lost on an interstate.

As for going to Mexico, you know both the US and Mexico State Department recommend you avoid it, don't you? The drug cartel is very active right at the border. I haven't heard of anything happening lately, I believe because people just aren't going. But a school assistant principal from Los Angeles and a tourist couple from Wisconsin were randomly killed a couple of years ago, just about this time. The Hall family was ambushed right outside Tijuana is lucky to be here today ~ they were taken up into the hills and left for dead (young parents with teenagers),
- There are many more… These are the awful ones I remember.

You can always use a MAP!

BTW - If you're planning to go to Mexico, you do know you need a passport, right?