The Second Life Mainland is filled with a vast railway track system and you can even ride your own train. Do a search or look on a mainland map for train tracks (usually close to roadways) and find a main train station where they have free trains or you can find trains on Marketplace. Make sure it advertises that it works on SSRL. There are more than 80 sims of tracks and vast and various routes.
My train has a car for 4 passengers and along the way I had several people hop on and ride a ways and chat. More fun than a handful of lag!