I just got my first. The Abernathy farm is supposedly under attack, but I'm in the middle of something. I did some searching and figured out this type of quest is timed, but I failed to find any info how long does it take to auto fail. So how much time I have - few hours? days? week? I just want to mop up what I started and walk back to them.

I'm not sure. All I know is that if you fast travel a couple times, you'll fail it.

For myself, I'm f***ing sick of these quests. Their frequency is way too often. I'm done with the main quest, doing side quests and exploring, and they always pop up right when I've traveled 3/4 of the f***ing map to get somewhere.

[censored] this sh*t.

About half a day I'd wager, I got the defend the castle at the start of the Covenant mission, then failed on my way literally out the door of the mission after the girl died and I got my reward.

build more defenses bruh

^^ That

The higher your Defence rating compared to your Pop/Food/Water, the less often you'll see attacks. At Sanctuary, I have 24 Food, 46 Water, and 112 Defence, and Sanc hasn't been attacked since the first days after I had something to raid.

As for going back, you have to bite the bullet and just head there immediately. Enough turrets/settlers and you won't have to do anything - just watch the show. Make sure you talk to a Settler afterwards to close the Quest and get back to what you were doing.

or....you know.....fast travel, which makes it A LOT faster, and IMO, has little effect on immersion, you can even rationlize it with the fact that teleportation DOES exist in the fallout universe now, or Vertibird transport if part of the BoS. or, you know the fact that time still passes, it is just skipping the whole "walk for miles through area's you have already seen and see nothing new"

One little tip: SAVE before going to defend missions. They have a habit of glitching out and either failing even when you kill all invaders, or just staying on your missions list in the pipboy forever.