What is all in CJ's list that it could take 4 months before Micheal could start his search? Here is the list as we know it.

Fix Gate
fix walls (reinforce walls)
Retrieve and fix 50 cal
Take inventory of the armory
Parts to fix wall
Parts to fix gate
Remove bodies
Clean water truck refilled
Fix generator at water well
Train colonists on weapons

Search for them
Tanya's research

Here is a couple things I'm guessing are also on it.

Fuel /fluids for the bird
Reset and add more traps
Plumbing project Sean was doing
Gather more food for winter

Here is some wild speculation

Build Underground tunnels to buildings outside of the colony