This is the Amplifier I ordered. These are only sold in a kit now. I will probably eBay the external antenna, although I may mount these in my car, and install power cables for the amp so I can move it between vehicles. I doubt I'd need it though--seems like too much work. My goals is a good data signal when I'm camping. I can use the indoor antenna if I want to boost my phone signal also. I think this would be a great option on a boat also.
Wilson Electronics 460108
It includes a path antenna for indoors, or you can bypass that with a cable direct from a MiFi.
This is the cable I'm using from my MiFi.
The JetPack I bought, which requires a nano to SIM adapter:
Amazon.com: Verizon Jetpack MHS291L 4G LTE Mobile Hotspot (Verizon Wireless): Cell Phones & Accessories