For finding the maps step of the quest I’ve found Nessus: over looking the radiolarian lake by the lost sector (from the well of flames pillar, find the big tree, look left, and there’s platforms over the lake) Tangled ashore: by defeating an ogre where you go to fight the Mindbender Dreaming City: following ascendant platforms up in the blind well entrance Edit: there’s a bug with the quest right now that after you do the ascendant challenge, you can retrieve the rest of them from Petra.
You can also repeat map fragments. I did the hive kills and acendant kills and only one nightfall which gave me another acendant kill bounty. Did that one again rather than 2 more nightfalls, completed the strike, got the Truth. RIP Gambit invasions... lol, and people thought the Sleeper was bad. Just wait and see. ;)