He can be found at approximately (-25, 216, -467), south west of the Bane Assertion Point CP but outside the main Bane base in the southeast.
Daddy Long-Legs, aside for being a relatively high level mob compared to those found around him, hits hard and has a lot of health. Waiting until he targets another player or NPC before engaging him is a good idea. As with all Striders, attacking from behind will keep him constantly turning around to try to face you, thereby spending less time attacking you. Another tactic is to drop high level EMP bombs as you run through his legs.