Ghusl for Entering Mecca
And whoever can talk a ghusl (bath) before entering Mecca then he should do so. And he should enter Mecca in the day following the example of the prophet of Allah. 
And he should enter from the upper part of Mecca which today has Bab ul Mi'lah as the Prophet entered from the upper pass (Kada')  above the graveyard, and he entered the masjid from Bab Bani Shaibah as that was the nearest way to the Black Stone (Al-Hajrul-Aswad).
And he is allowed to enter by any path as the Prophet said: All of the mountain passes of Mecca are a pathway and place for slaughter and in another hadith, All of Mecca is a pathway. He enters from here and leaves from here. 
So if you enter the masjid do not forget to enter by the right foot,  and say:  allallhumma salli `ala muhammadin wa sallim - allahumma aftah li abwaba rahmatika or a'udhu billahil `azeemi wa biwajhihil karim wa sultanihil qadeemi minash shaitanir rajeem.
And when he sees the Ka'bah he raises his hands if he wants to - as it is established from Ibn `Abbas. 
And there is no du'a established from the Prophet at this point. So he may make du'a with Whatever he can if he wishes with the du'a which is established from `Umar: 
allahumma anta salamu wa minkas salamu fahayyina rabbana bissalam