Image: UbisoftOfficial screenshot from Ubisoft.
Backpacking means owning every Supremo, the backpack super weapons Dani wears. Most are bought as the story opens them up, but one comes only from the Triada Blessings side story.
1. Finish Libertad Rises so Supremos go on sale. 2. Destroy Anti-Aircraft Sites to collect Depleted Uranium. 3. Buy each Supremo as it becomes available. 4. Complete Triada Blessings for the Triador. The trophy pops when the last one is yours.
Triada Blessings sends you after three idols through Treasure Hunts in Madrugada, Valle De Oro and El Este, so do it while you clear those regions. Knocking out AA sites early keeps your Uranium topped up and opens the skies at the same time.