It's been about a week since I last worked on this game, although here on the blog, it's only been a day! The wonders of writing blog entries in advance. Well, here's everything I found out today.
1. You have to have the trivet, in order to open Josiah's journal. I figured as much. It would have been a big timesaver, if you didn't HAVE to get the trivet.
2. You can look at the sewing machine at any point in the game, but in order to zoom in on the sewing machine--and notice it needs a needle--you have to have the dress in your inventory. So looking at the sewing machine earlier doesn't really save time.
3. If Nancy runs out of gas, then she's transported to Zippy's, where she has to do a sorting puzzle. It was long and complicated, and there's a conversation between Nancy and Zippy the precedes it. In the interest of beating the game quickly, I'll try to avoid this. The good news is that you can't run out of gas, during the endgame challenge.
4. Nancy's dad will automatically call you, if you ignore him long enough. You can also call him at the very start of the game, before meeting Jane and Emily. If you call him early on, the conversation is shorter; Nancy doesn't talk to him about the mystery or the characters, because those things haven't happened yet.
So I guess I have to test out those two Dad conversations and figure out for sure if one is shorter than the other. I bet when you call Dad also affects a few dialogue options with other characters, like when Jane tells you to call Dad. Maybe?