Was hoping someone could point me in the right direction or check if I am in the right head space on how to tackle this project.
I would like to make my own animal alarm trap system, so that when the animal is caught, or once the trap is triggered I get a message sent to my phone. This is for animal relocation purposes not hunting (to all you animal lovers out there 
).
Based on what I found GSM modules (SIM900 or 800) would not work as I live in the United States and 2G networks are now more or less obsolete.
The MKR GSM 1400 Cellular kit sounds like it would work great. It would be triggered from trap movement, then send signal to nearest cell tower which then goes to the Arduino IOT cloud where then I can use Webhooks and API to send text message to iPhone.
Then I was looking at the MKR NB 1500 which seems promising since Arduino says "It's the perfect choice for devices in remote locations without an Internet connection, or in situations in which power isn't available like on-field deployments, remote metering systems, solar-powered devices, or other extreme scenarios." This sounds very suitable, as the device will be in the wilderness and there may or may not be internet connection at times. I just don't understand how it sends a signal, or how it would get to my phone? (narrowband?)
Not entirely sure if MKR boards are the best option for what I am trying to do (maybe too expensive or overkill). I also know that sending signals will be tricky as trees and things in the outside environments can interfere with the data transmission (that's a whole other problem). I do want to build it myself so off the shelf built things are a no go.
Any help would be greatly appreciated!