Use the Mod Organizer 2. It uses a virtual file system (means original files are untouched) and allow different mod profiles. In case something goes wrong it's very easy to switch back to a running installation by the click of a mouse button.
I recommend following this guide: https://vivanewvegas.github.io/
It's stable (one of New Vegas biggest problem) and doesn't change to much from the original experience if you play it the first time.
As for the Frontier mod: after seeing what people did with Enderal: Forgotten Stories which feels like Gothic made in Skyrims engine and is really really amazing, I'm surprised what hobby devs achieve in their free time.
Will try out that mod!