Best way to set up WLAN without internet?

Hello everyone! A little background:

I am an astrophotographer, which means i take a lot of computers out into the mountains away from all wifi and even cell signals. I use an intel NUC attached directly to the mount to run the telescope and the cameras, and when i’m at home i use teamviewer to remote access the NUC through my laptop or ipad.

My issue is that i need to be able to do this when there is no available internet or cellular connection. I already know that both computers use Intel hardware that does not allow ad hoc networks. Is there a USB-based option that will allow the NUC to broadcast a signal that i can connect directly to, or would i need a physically separate router? Also, would teamviewer work under a local network with internet connectivity?

Thanks for taking the time to ponder my dilemma!