One of the most important things you can build into these documents is a clause that allows you to perform proper "due diligence" on the property. Basically you want to make sure that you have time to review all of the necessary financial information, management documents, and fully inspect the property itself BEFORE you finalize the purchase of the property. If things are not what they appear to be on the surface, it is better to find out now _ before you own the property than 6 months down the road.
Moral of the story? If you're ever contemplating using a Letter of Intent in a business transaction, you had better watched out, it may not be as simple a matter as you might think. You better be very cautious, for it could result in unforeseen and unpredictable consequences!