Yesterday was the good news that minigolf is optional. At least, it's optional as far as the carriage lock puzzle is concerned. Is it optional when it comes to saving money? Sadly, no.
Nancy starts the game with $3.50. That perfectly matches with Mr. Waddell, who charges her $3.50 for the key and quartz. Those two things cancel each other out.
Nancy gets $1.00 from the underground passage. She has to spend money, to get five toys. She can get a toy for 10 cents, through golf. She can get a toy for 25 cents, through the store. Math dictates that Nancy must play miniature golf 2, 3, 4 or 5 times, to keep the cost of toys under $1.00.
If not, you have to deliver telegrams, which takes time, and should be avoided in a speedrun.
So...this means my speedrun route will include playing miniature golf twice, the fewest number of times possible. I will have to change the route, if it turns out that it's impossible to beat the game without delivering telegrams or paying for gas, because both of those things affect the finances.