How to Fort Loop

So you want to instantly teleport your troops from one city to another one that's very far away.

Let's say your main city is at point (0,0) and your first sub city is at (400,400). Suppose there is a fort at point (0,1).

Step 1:
Attack the fort twice from point (0,0) to get it down to 20% loyalty.

Step 2:
Send your third attack from point (400,400) and occupy the fort.

Step 3:
Send any army from (0,0) into the fort.

Step 4:
Go to the Fort tab, select the fort, and tap Recall.

Step 5:
Ta-da! Troops are sent automatically to your second spot instantly!

Additional tip:
Spread your troops out in a nice circle. Main City troops recall to Sub 1, Sub 1 troops recall to Sub 2, Sub 2 troops recall to Sub 3, etc. The last sub's troops should recall to your main city.

Tip #2
Since end-game players often go after each other's fort loops during war, I recommend getting low level forts (level 6 and under) for the sake of convenience. You'll get a little less money per hour, but by the time you are end-game, must of your money should come from hunts.