Anyways, the Verizon S4 is rooted and is still on original MDK firmware. With that said, I'm not too sure exactly which steps in your guide apply to our situation...not having safe strap and all.
With changing the APN settings to match up to my phone (LG G3 on T-Mobile), and inserting a T-Mobile 4G sim card, I'm able to get calls and SMS working over WiFi on the S4...that's it though. No mobile data seems to be coming through. Her mobile signal icon in the status bar keeps switching back n forth from E to H for some reason...but no LTE or 4G icon.
Anyways, is this something anyone thinks they could help with? Or do ya think we're screwed? My sweet wife would be eternally grateful if someone could help to make this happen!!
EDIT: haha, my signature will be changed if I'm able to get this working for her!