LOL as per every Bethesda game in history it's incredibly easy to get sidetracked in FO4. I've gotten caught between flipflopping missions for the Minutemen and Brotherhood and building settlements.

My question for people who're further along in the main quest than I am; are there penalties for ignoring these quest lines or can I come back to them if I go looking for Shaun?

getting sidetracked in the entire point of the game. Enjoy it, explore everything.

Hey

Yeah tell me about. I wasted 7 hours yesterday just trying to get one building just right.. I just can't seem to make a two storey building look good. Doesn't help that the tiles aren't good enough to do this

Other than that I do like to explore and love just going places that involve quests.

Voice

Just completed the game, yes you can carry missions on for them after the "end game" quest.