Okay so this quest is a bit on the broken side..
You're supposed to jump on the giant ass bug and race back to the cave where your friends are waiting. Kiro jumps on the front - in the driver seat - and somehow you're still the one who's driving. Your giant ass bug has a skill which (I assume) is supposed to one-shot mobs like Brutusk does, but sadly does hardly any damage at all, and - in the case of the citizen groups - can end up pulling a whole army of snakemen who will slaughter you. The good news is, there doesn't appear to be a way to fail this quest. You can climb back into your corpse, head back the way you came, and hop on another deathtrap bug, and start over.
"Following the path" isn't easy. If you stray too far in any direction, or pick a wrong turn, the giant ass bug despawns, dropping you on your ass, and probably in a gaggle of pissed off snakemen hungry for your blood. If your don't die, you can always head back and pick yet another deathtrap bug and try again. Eventually, you'll get to the right path, and when close enough to the cave, Kiro jumps off, says something out of a B-movie, and you runs inside, at which point you can follow and hand in the quest.
Interestingly, if you take the path above the cave, the giant ass bug does not despawn, but you are dropped on your ass. At this point, you can wander all over with a giant ass bug pet, driven by the reluctant Kiro, however it remains docile, making it little more than a cosmetic. You can head towards the cave and turn in the quest without issue.