Yes, you have got enough time. Holiday Inn Downtown at 585 Heng Feng Road is close to Shanghai Railway Station and not far from the Bund.
You can take Airport Shuttle Bus No.5 to Shanghai Railway Station and then walk to your hotel. As for the transfer between the hotel and the Bund. You can take air-conditioned bus no.929 from Shanghai Rialway Station.

How long is the walk to the hotel? And can you also give me direction on how to go back to the airport in a most efficient way from the Bund?

Do you know hotel names alongside the The Bund?

The Hotel is just located to the west of the Bus Stop, you could walk there in 5 minutes.

At the Bund, you could take the subway Line 2 to reach the Longyang Road station firstly and then transfer to the Maglev train to get to Pudong Airport in 10 minutes.

Or please take the subway Line 2 to the Jing'an Temple, where you could catch the shuttle bus Line 2 to arrive at Pudong in one hour. Actually, the firstly method is recommended.

There are many hotels along the Bund, such as the famous Peace Hotel.