How should business owners think about capital gains, ordinary income, and distributions?

All of these are tied together somewhat. Capital gains is typically going to be the lowest tax rate for our clients. This means investment accounts can sometimes cost less to get money from than a traditional retirement account.
Your ordinary income rate is the tax rate that everyone typically talks about. When you take money from a traditional retirement account, you will have to pay ordinary income tax. If the account is big enough, the amount required to be pulled from it can cost more than capital gains taxes.
Distributions can be taxable or non-taxable. For example, in an S-Corp, you can sometimes take distributions with money that has already been taxed. All of these things can impact each other to help or hurt your tax situation. It takes someone looking at all of them together to determine what is best for your family.