All documents related to property are public documents and as there was well laid down procedure for seeking such information through certified copies, RTI is not necessary.
You can obtain encumberance certificate and certified copies of documents with in one week from Sub-Registrar on payment of prescribed fees .
You can seek information on mutation and documents filed by the parties under RTI to the concerned Panchayat, Municipality or Corporation.
You can also secure Extract of tax paid receipts from authorities.
In cae of property matters, it is only the Regd.sale deed and other connecting link deeds matter, and they can be obtained from Registarar.
Incase the property was acquired through process of court, application can be made before concerned court for CC of that judgment through advocate.