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.
Incidentally, the idea of working with a business plan is for one to keep focus on his set goals. Statistics has it that many businesses fail due to inadequate planning. If one doesn't know where he's heading to, any route seems to be the right one. Most people make great mistakes by jumping into business without adequate preparation and planning. A good business plan helps one maintain focus on his goals and execute the strategies that the plan assisted him in creating. Just like a road, one's business plan has to be consulted to make maintain his focus and not running business in a layman's way.