I copied this from the old forums, for those who need it. I found it helpful as a returning player.
"Seeing as a lot of clones seem to be getting confused with the ATV mission chain now I thought I would put up a post that lists the New NPC's, what they are called, where they can be found and what knowledge they supply.The mission chain appears once you are at level 5, and sends you to Embry to talk to the first NPC. Note, no other part requires a specific level to do, but be aware later stages will be hard to complete at lower levels, as they are in areas where the mobs can reach up to lvl 13. This is NOT a full walkthrough, just a guide as to who and where the main NPC's can be found.Also please note that you can no longer get the knowledges from the old mission chain, although you can still get parts for doing them. (Currently there appears to be an issue when doing Messner Cook's Questline, in that you get told that you will be given a Control System but do not receive it. If this happens to you please report it immediately to the GM that is on Duty.)New ATV Questline.John Harris /Loc 4256935, 3233268Control Systems 1 Knowledge.From there you are sent to Linewood.Paige Morrison /Loc 4326870, 3582582Tires 1 Knowledge.Then it's on to Old KingmanZahara Reeves /Loc 4174870, 3588701Frame 1 KnowledgeZahara wants you to check on her brother who is in the Junkyard surrounded by dogs.Zack Reeves /Loc 4167700, 3580407From here you are sent to Needle EyeGarret Copeland /Loc 4304151, 3754251Engine 1 Knowledge Then Finally on to Pass ChrisLonnie Parker /Loc 4506829, 3807750He then wants you to meet him at the Night Wolf Camp /Loc 4579608,3745292From there it's back to Pass Chris.(By request, as this part seems to be causing some problems)Once in Pass Chris and you speak to Lonnie again, you have to work on the junked ATV, What this means is attack it until its destroyed and your clone is knocked off their feet.Once you complete the quest and gain the ATV Knowledge, you also receive 2AP.Hope this helps you out in the wasteland.Sasha Delmorna. "