Charlottesville–Albemarle Airport: Rent a car at the airport; Keswick is roughly 25–35 minutes east via local roads, and a car is essential once there. A rideshare can work if pre-booked, but expect roughly $35–60 each way and thin return availability. There is no useful airport-to-Keswick public transit.
Charlottesville Amtrak Station: This is the sensible rail arrival point, about 20–25 minutes from Keswick by car. Book a rental car or arrange a pickup; a rideshare is usually around $25–45, but do not count on finding one easily for the return trip from rural Keswick.
Richmond International Airport: Use RIC only if its flight schedule or fare wins decisively. Rent a car for the roughly 1 hour 20 minute to 1 hour 45 minute drive; a one-way private ride or rideshare is usually an expensive proposition, often well over $100. There is no direct public-transport transfer.
Washington Dulles International Airport: A rental car is the practical choice for the roughly 2–2½-hour drive, depending heavily on Northern Virginia traffic. It is a viable international gateway, not a convenient local airport; private transfers commonly cost far more than a rental car, before tolls and tip.