From Pu Dong airport to Holiday inn Downtown

Yes, you are right. You can take the airport shuttle bus line 5 to reach its destination at the local railway station and then walk to reach your hotel along Hengfeng Road.
If you want to take the subway, you need to take the subway line 2 to reach People's Square Station first and then change to take line 1 to reach Railway Station. Get out of the station from Exit 3 and then you can easily find your hotel.