Since your mission statement is only a few pages long, your executive summary will allow you to further expand upon key points mentioned in the mission statement. Consider including your business history, biographies of key players, an overview of the business including locations, employees and available products and services. You can also discuss goals and future plans. Use this section to really draw in the readers.
In many cases business plans are very important but so much of the time it is a plan to try to convince someone else that you know what you are doing with your business like banks, investors, partners, etc. Now it is true that a well written business plan can also be a major benefit to your success as well if done right. It can guide you and keep you on track and can be the vehicle to get you were you want to be especially with so many outside forces now days that bombard you. A plan can be extremely important to your success especially when you look at the statistics that says 51% of small businesses fail sometime during their first 5 years.