So I was having a lot of the same problems as other with trying to extend my network, make it more stable and compatible with other wireless devices. I've gone through three 4G devices (Samsung then MiFi then back to Samsung). Here in Columbia, SC I still don't get a consistent 4G speed but at least I am now fairly stable with my 4G connection at better than 3G speeds so I'm ok with that until something else comes along.
Here's how I have my home network setup using my VZW 4G Samsung device. Keep in mind that I also have a cable modem that I use for most Internet activity due to the 10GB limitation with VZW.
What you need:
Why/How does it work?
The Ethernet WiFi adapter "tricks" the router into thinking it's connected via ethernet to a modem.
At this point your router will typically boot up and obtain the connection information from your hotspot just as if it were connected to any other modem. Now you can connect to your routher via it's wireless connection or one of its wired ports. If all goes well, you are on the internet through your hotspot. If not, you can try powering down the router, waiting about a minute and power back up. If that doesn't work, you will need to connect to your router via your web browser and try a release/renew of the IPs but this is not a typical occurrence.
Good luck! Oh and be careful! It's easy to forget you are on a hotspot and have a data limit.
Okay, the first question I have (purely out of curiousity and not trying to start an argument) if you have cable modem why are you using 4G? If I had any other possible option for internet available I would never submit myself to the pain that is Verizon 4G.
I have kind of the same configuration but I am using PC with wifi usb adapter to be the routers connection to the internet. That is why I am totally annoyed I can't tether as that would be so much more stable...