This command will create a machine that allows you to setup your own Fast Travel destination and drink potions to instantly teleport you to that location. It will also support Vanilla Multiplayer servers without any issues.
To get setup all you need to do is place a single command block and paste the bellow command into it. Run it once by applying redstone power to the command block. The structure will generate out West (towards negative X) from where you've placed the command block.
Setting your Fast Travel target
By default there is no fast travel target set. In order to set the target location that you will be teleported to you will need to right click on the "Reset Fast Travel Target" sign that is on the machine. This will destroy any previous targets you have set and will give you a special ArmorStand that will be used to set your travel target. Just place the ArmorStand at any location and that will become the destination you will be teleported to when you drink the fast travel potion. (note: If you try to set multiple targets by placing multiple of these ArmorStands in creative mode the machine will just teleport you to whichever is closest to the machine).
Getting A Potion
On the machine there will be a sign to "Get Potion Dispenser". If you right click this sign you will be given another sign that when placed acts as the dispenser for fast travel potions. This will allow you to place dispensers around your world so you can always get a new fast travel potion if you find yourself without one. Right clicking on a dispenser will cause it give a fast travel potion to the nearest player.
Using the Potion
All you need to do to use the Fast Travel Potion is to drink it. Upon drinking the potion you will be immediately teleported to the location where you set previously by placing the Armor Stand. When you are teleported the system will check your inventory to see if you are now out of Fast Travel Potions and if so it will remove one empty bottle from your inventory and give you back a new fast travel potion.
Removing the Fast Travel System
To remove the Fast Travel System all you have to do is right click on the "Click to Remove" sign on the machine. This will delete the machine, remove your fast travel target, and clean up any scoreboard objectives that are used by the system for fast travel. This will not remove the Fast Travel Potions or dispenser signs from the world, but you should be able to easily do that yourself.
I initially created this system so that I could create a fast travel hub to use on a multiplayer server with my friends. By setting the Fast Travel Destination in a central hub room that contained other command blocks to teleport players to different parts of the world I was able to make a quick and easy travel mechanism for players on a pure Vanilla server.
If you have other uses for the system I'd love to hear about them in the comments below.
If you have any feedback or bugs to report please do so in the comments bellow. If you like this command please remember to favorite it so I know people like it. If people are interested in having me post a command block tutorial on how the system works please let me know in the comments and I'll be happy to put together a tutorial.