Has anyone made a standalone mod to add the vehicle system to FNV? I'd like to try disabling fast travel and maybe using something like a motorcycle to get around (because immersive and such), but I don't want to touch the Frontier (because degenerates and such, also it's 10 fucking Gigabytes).

Frontier has best vehicles so far.

Some alternatives are XRE mods (2012):
XRE beta1_35 showcase - Flyable Vertibird
XRE - CARS v0_86

Or something ancient like this (2009):
Driveable Chimera Tank
J3Xified Driveable Motorcycle

I remember discussions from 2010, where most of the community didn't want vehicles. Also making a vehicle mod is incredibly difficult task.

If you want vehicles, bite the bullet and get the Frontier.