Warren—and the surrounding towns where lodging is—is about an hour away from the Burlington International Airport. We'd highly recommend you rent a car. Public transportation is basically nonexistent; Ubers or Lyfts are not a thing. A rental car will obviously allow you to easily get from the airport to your abode, but it will also let you easily check out all that the Mad River Valley has to offer—which is a lot!
The drive from Burlington International Airport to Warren, VT is approximately 1 hour. The airport is small and incredibly easy to get in and out of!
The rental car companies at BTV are all conveniently located inside the terminal, on the main floor, adjacent to the baggage carousels. Rental vehicles are a short walk from the counters via a covered skywalk and are inside a parking garage—protected from rain or snow.
https://www.btv.aero/at-btv/ground-transportation/rental-cars