Is prayer within the bounds of the Prophetic Sanctuary [Al-Haram Al-Nabawi] like prayer in the [Grand] Sanctuary [Al-Haram Al-Sharif] in terms of reward, and similarly in Mecca?

The reward for prayer in Al-Masjid Al-Haram and Al-Masjid An-Nabawi is multiplied. Prayer in Al-Masjid An-Nabawi is better than a thousand prayers in any other mosque, except Al-Masjid Al-Haram. Prayer in Al-Masjid Al-Haram is better than one hundred thousand prayers in any other mosque.

Scholars have differed regarding "Al-Masjid Al-Haram" where prayer is multiplied: whether it is exclusive to the Kaaba mosque or includes what is within the boundaries of the Haram. The preponderant opinion is that it is exclusive to the Kaaba mosque.

As for Madinah, there is no multiplication of reward in its sacred precinct; rather, the multiplication is specific to Al-Masjid An-Nabawi. Scholars have differed regarding whether the multiplication of reward extends to the extensions added to the mosque after the death of the Prophet, peace and blessings be upon him. The majority opinion is that prayer therein is multiplied just as it is multiplied in the original mosque.