Epic Chef

I didn't get this until around Day 70, but the best method I had for making money was planting a lot of Erwin trees. Wait until there are 3 or 4 fruits dropping, then collect all the fruit. Chop down the trees and sell the logs (individually, not as planks). Birch and linked containers were also helpful when I was making runs into town to sell. Apple trees are a good alternative if you're not at Erwin yet.
It's also worth mentioning that the higher your prestige rating is, the more gold you get from your restaurant. Unlock as many patrons as you can, and try to improve their star rating as much as possible. Or, doing quests for people will also get you some money.