I concentrated on updating the stills as soon as I was able, as they allow you to make stronger moonshine and earn more money. Only downside is the stronger the moonshine, the longer it takes to make, but one of the higher levels rewards you with an item that slightly decreases the time (a pamphlet, I believe).
I play solo, so upgrading the bar and band areas wasn't a priority, but they are necessary if you're after the gold from daily challenges, and I imagine a lot of fun if you play with friends.
Lastly, the Norfolk Roadster is one of the better horses available, in my opinion.