Solving the long trivet puzzles gets you the ham radio numbers. I think what you do at this point is talk to Topham, and he refuses to give you access to the Shakespeare book. Maybe you can do this earlier? I'll have to double-check what the trigger is, for asking about the book.
I believe that asking Topham about the book triggers the scene, where you can use the hidden tunnel to break into Topham's house. Again, that's a trigger I'll have to research. It could be that there's another trigger entirely, like getting the quartz from Waddell.
So you break in Topham's, give the mouse to the cat, and get the cues. At this point, the game is linear. You give the cues to the correct people, so you can solve the hobo sign language puzzle, which is followed by another puzzle. This gives you a golf ball. Use the golf ball to get the key. This triggers the endgame challenge.
And that's it! That would be my speedrun route for "Nancy Drew: Secret of the Old Clock"! It requires a lot of work, as I determine what triggers what, and change the route accordingly. Also, there will be a lot of work, determining the fastest way to do all the driving challenges.
Tomorrow, I'll have a big bullet list, just as a general outline.