At the risk of pushing this too far into taxes... Vanguard offers a "HIFO" approach to shares sold. The highest cost is sold first, resulting in the lowest taxes. If you don't want to think about it, or don't have much of a mix of long-term (1yr+) and short-term, it could simplify it.
It's significant that this is your existing business, and the 200k is for new locations. If this business does better than average in current conditions (per your own knowledge), maybe it's better than a market investment.
Note you are increasing your risk. Your income is heavily dependent on what you already do, and you're taking investments spread over the whole market, and focusing them in a similar business to yours. If that business suffers problems, you could lose your job and that investment at the same time. It's important to look at that risk, and make sure you're comfortable with it.
Hope it works out well, either way.