
I don't know if this is just me but my saves aren't keeping the total amount of scrap I receive after logging back into the game. Later areas don't open up until you've reached various points in the story and you'll need to do some serious upgrading on the side to be able to deal with the enemies and bases in the later areas. There are 4 or 5 different strongholds across the game world which all have scrap crews so to earn as much as possible while the game is off you need to unlock all of them but obviously this will require a considerable amount of play time.

I'm guessing it's not very much with just the one scrap crew (maybe as little as 10 scrap per hour but don't quote me on that) and you'll receive it next time you load into the game. Once you've found all the parts of the scrap crew then it will start generating scrap while you're not playing the game. The scavenging locations can be just a deserted area like a few abandoned tents, a little camp with a handful of enemies or a massive base with dozens of enemies and defenses. It will take maybe a few hours of playtime to reach the stronghold through the main story and then you need to collect multiple parts from different scavenging locations in the local area, most likely 3 or 4.

You'll need to unlock the scrap crew for the first stronghold you come to in order to get started. If you're mainly looking to get the two challenges that seem like they're going to be affected by the server shutdown then it's not so bad at all.
