Sounds like a fun infiltration (partly at least) and following battle! Your group souns like they are playing smart, with recon and pretty good stealth approach! They did something similar at the first adventure as well...

Can you add the map locals key tonehere they've been, perhaps as spoilers? I happen to have thebold module (in Hebrew, but still). It can help figure out their progress, with your story.

And thanks for keeping posting this! :)