We have 1 week until our third main quest is due, and we have 2 side quests available. Do side quests expire if you don't do them before a main quest, or do they stay until you complete them, or do they expire once you do the interlude? Just want to know as choosing the side quest now means we can't go to the city to regain lost morale, but choosing the main quest may mean we lose out on a potential side quest. We completed a side quest, had no side quests available so we to town, now 2 spawned with only a week left, hoping we can save them.

we are going through Kindred Fire.

After you do the main quest, they will still be available until you go to town. Once you go to town (and leave), you will likely loose those ones and gain two more.

If you were to wait one week in town, you would likely loose the quests and be forced to take the main quest as your next travel step.