Access to Buildings??,

Have all your characters out at the same time & see who gives you a quest/s

Example: if homer's quest lasts 4 hrs. Then send out all the remaining characters that are not on quest on 4 hr jobs. When you complete the quest, finish everyone else's jobs & now you will have them all again. Rinse and repeat. This is the fastest way to get all quests done and to unlock all buildings.