Get the Garmin USA app, it puts all the data on your phone/iPad so you don't need data access. I've been using it for some time now and I rally like it. $35 is expensive for an app but well worth the price! Double check that it works on the iPad.
I would agree on the Hummer H3 I really like mine. It's also the most comfortable vehicle for long trips I've ever owned. Fuel milage is good and it comes fully capable to tackle pretty much anything if you get an adventure package (my 2009 is locked front and rear). You would save money on mods...
I was just out that way. Drove 5088 mile from PA to AZ and by the time I reached Colorado my wife was fried from driving next to the edge. I had to skip the Alpine loop but "I'll be back". Looks like I missed a beautiful drive.
Thanks for sharing your journey.