I (the DM) had this thought that the familiar who belongs to an evil wizard far away from the players was delivering a message to the Bugbear leader of a band of goblins who was under the command of said wizard to search an ancient crypt. Can a familiar be given a command to travel that distance and deliver a message? The only thing I can find regarding range in the PHB is 100 feet for telepathic communication and 1 mile for empathetic communication.
The familiar can travel any distance from the caster. The rules only limit communication, not travel. Also, someone else recently asked this to Mike Mearls, and he confirmed that is what RAW and RAI say: Does a familiar have a max distance it can be from it's master?
Those limits on communication are greatly expanded for Warlocks with the Pact of Chain boon and the Invocation Master of Chain -- where the familiar can be communicated with, and see through senses used, anywhere on the same plane of existence.