Have an FTP server currently full of PDF files (mining permits and maps that are geotagged). Multiple users log in and currently download and print what they need before heading to a mining site. (yes coal mines)

Wouldn't it be great if these PDF files were on an iPad! Yipee! Wait:

1.) User won't have 3G access in the middle of no where, will need to make an app to sync down the files in advance

2.) Some users may have access to 60GB of files and only have a 16GB iPad. So they need to be able to select what they want to sync.

3.) When permits or maps are updated the iPad needs to know to download the latest version.

4.) One guy asked me "Can we geo-sync those PDF maps to so we can see where we are when we are in the field"

I was thinking a custom interface using FTP initially, but now this seems like a monster project and I don't know where to begin.

Any advice??? I am ready to hire someone to get it done, probably beyond my skills. Would enjoy learning on the company's dime.

-Jessica