If you want to drive from Athens to Gythio, you take the National Highway that links Athens to Corinth. After you pass the Corinth Channel, you take the Highway to Tripoli. From Tripoli, you continue to Sparti. Note that the road after Tripoli is not a highway but a rural road, so there is only one line per direction. From Sparti, you follow the signs to Gythio. The distance from Athens to Gythio is 270 km, while from Sparta to Gythio is about 40 km.
In case you don't have your own vehicle, it is an excellent idea to hire one for your sightseeing trips!
> Rent your car to Gythio!