My bad, getting bushels from friends resets at the same time every day, no matter when you start. It's like daily quests in World of Warcraft.
- If you don't get bushels from some friends before the time is reset, that chance is wasted. e.g. Sunflowers are in high demand, make sure you get all the bushels available before reset.
The pig pen's truffle hunting timer depends only on when the first pig goes hunting. If you are in a hurry and can't do all 20 pigs, just do one first. The timer will start earlier, and you can do the rest at your leisure.
Example: it's 12 noon. You're going out and coming back at 8 pm. If you wait till 8 pm and hunt, you can only hunt again 2 days later at 8 pm. If you hunt using one pig now and the other 19 at 8 pm, you can hunt again 2 days later at 12.