Crossroads is a shopping and restaurant area at the crossroads (strangely enough!) at the entrance to WDW on the east side - off Vineland Road (SR 535). Its only about a mile and a half from the bottom of I-Drive but I-Drive is very long.
Its probably nearer 3 miles from Pointe Orlando/the Convention Centre which is the end of International Drive for most people.
There is no charge for Downtown Disney and the parking is free. There is a charge for the night club area of Pleasure Island.