There is no filtering through legally written clauses and other such unnecessary information at this stage in the project. When the letter of intent spells out each detail clearly, the seller can come back with alternate terms of which he or she would be more accepting. This negotiation can go back and forth without the rewriting of lengthy pages that either party may misconstrue.
Here is an example of a good "Due Diligence Clause" you can use: "Seller to provide the following for buyers examination and approval in the next 30 days: 1) All leases, 2) All property management agreements, 3) All vendor contracts, 4) Current Rent Roll, 5) Property Income and Expense History for the last two years, 6) Year to date property income and expense history, 7) Last two years tax returns as they pertain to the property, 8) All units, buildings, grounds and mechanical systems. Buyer may void this contract at any time during this 30 day period if the information found does not meet buyers approval"