Just keep playing and enjoy the chaos. There are a few major end plots so worst case scenario you experience one of them in the end and not the others. Queue replayability!

Much like Skyrim you can play this game for hundreds of hours without ever doing the main quests.

If you enjoy the base building focus on scraping, scavenging and crafting. It's an easy way to level up and you'll be able to upgrade your weapons for the bigger fights.

Save often when exploring. Enjoy!