What if I want to farm Hearts of the Foreign God? If you want Heart drops, you're going to need to sacrifice some of the shop, unless you're willing to spend apples. The most efficient way to do this is as follows:
Clear all quests once as soon as they unlock, while spamming 5AP for the gold dango in between. You'll probably be running with an Automaton and a friend Automaton equipped, which should give you an average of 6-7 gold dango per 5AP run. With this, you should be able to unlock 30AP on the first day without issue. Then, run 30AP until you get 500 regular dango, and buy the Moonlight Fest CE. This may take upward of 2 days.
We farm 30AP first because this is when doing so is the "least wasteful." While 30AP is always less efficient than 5AP in regard to farming dango, it is "less inefficient" before obtaining the Moonlight Fest CE, after which you "lose" an additional 22-23 dango for every 30AP quest you complete.
After obtaining Moonlight Fest, switch to farming 5AP until you get 1300+ regular dango. This should take about 3 days, leaving only 1-2 more days in the event. I calculate that 1300 regular dango is probably the point that it's safe to go back to farming 30AP for Hearts, where the 30AP farm will get you the rest of the dango you will need by the end of the event. As the deadline draws near, you may have to do some math to figure out how many "actual" dango you have, remembering that gold dango will convert to regular dango after the event, at a rate of 2 gold dango to 1 regular dango. If you find yourself coming up short, it's possible you will need to go back to 5AP on the last day, so do beware of this.