Cyclops are very easy to kill and are relatively low combat level.
Bring potions only if you want to speed it up a bit.
I was around 80 combat when I got my rune defender and didn't need to bank much. Only about 2 times or so.
Of course, bring full inventory of food.
More info on cyclops:
http://runescape.wikia.com/wiki/CyclopsFull info on what you asked:
rswikia wrote:
The two main variations of cyclopes may be found in the Warriors' Guild. To get inside the Warriors' Guild, a player's Attack and Strength levels must add up to a sum of 130 or greater. In order to enter the Cyclops area, located on the second floor, a player must gain at least 100 Warriors' Guild Tokens. When inside the room, 10 tokens are used up every minute, and the player must leave when the tokens run out.
A single cyclops is caged in the Ardougne Zoo, but it does not drop defenders.
Level 81 cyclopes inhabit the God Wars Dungeon, but these too do not drop defenders.