Milkrun

Milkrun: noun, spacer slang for a highly profitable, but tedious, trade route. Also; milking: verb, doing a milkrun repeatedly.

Frontier

For example, in FE2 and FFE, the route Sol - Barnard's Star is the mother of all milkruns. It is very short distance, it is absolutely safe, and guarantees a good profit for every trip. You don't need any weapons or equipment other than Autopilot. Doing this route will put a spacer in the position to buy any ship they want within a matter of months.

Take luxury goods from Sol to Barnards Star and computers or robots back to Sol. Computers and robots are usually sold out in Sol so check the bulletin boards on the three orbital stations around Earth and the one around the moon for anyone willing to pay double. This makes it more profitable and a little more exciting.

Van Maanens Star is also safe once you have a permit and know at least one merchant. Smuggle Luxury Goods and Liquor from the Sol system and return with computers.

Oolite

Starting at Lave, there are three in the vicinity:

Leesti (Poor Industrial) to Diso (Average Agricultural). While both are safe systems, they are horribly close to anarchic Riedquat & Uszaa - and feudal Orerve, whose local pirates are quite happy to visit Leesti & Diso to prey on the shipping.

Zaonce (Average Industrial) & Tionisla (Average Industrial) to Isinor (Poor Agricultural). Isinor has some unpleasant neighbours, but Tionisla is pretty safe. Not as lucrative a milkrun as Isinor-Ensoreus, but definitely safer.

Isinor (Poor Agricultural) to Ensoreus (Rich Industrial). Isinor is slightly less safe (Confederacy) and close to some horrors, as is Ensoreus. But the disparity in wealth makes this the best milkrun in the vicinity (but dangerous).

OXPs

User:Redspear's Paddling Pool OXP changes the politics east of Lave to create a much safer milkrun between Leesti & Diso.