How to transfer file (PDF) from imac to iphone when no internet
You could always set up a local network on your mac. Then you can use Dysoft's Download Manager, it has a buit-in ftp/http server you can locally connect to.

It also supports transferring files through iTunes, using the Apps tab (Device > Apps > Bottom of the page: "file transfer").

There are probably a lot of other apps that can do this, but I use this one and never had any trouble.