Airport to the hotel: take maglev train or airport bus to Longyang Road, then change to SUbway Line 2 at Longyang Road and get off at People's Square. Get out from Exit 9 and you can jsut find your hotel next to the subway station. The cost is about 45RMB, it is 20RMB less than taking a airport bus, but not maglev.
Do you mean the expo center in Longyang Road in Pudong New Area? Of so, take Subway Line 2 from People's Square next to your hotel to Longyang Road. The expo center is nearby opposite the subway station.
Take Subway Line 1 at People's Square station to Shanghai South Railway Station for bullet train to Hangzhou. Get out of Hangzhou Railway Station to take Bus K7 to West Lake. Yes, you can purchase the ticket the same day of travel. If you want to go early in the morning, better to book the ticket the day before leaving.

1. please take the shuttle bus Line 2 (CNY22/adult) to arrive at its terminal at Jing'an Temple firstly. Just right here, you could trainsfer to the subway Line 2 (CNY2/adult), and then get off at the 2nd stop at the People's Square, where the Pacific Hotel is located.
2. Please take the subway Line 2 and then get off at Longyang Road station. From here, you could walk to the Expo Center easily.
3. Except of weekends, you could purchase train ticket on the spot. Well, you could take the subway Line 1 to Shanghai South Railway Station, where there are bullet trains to Hangzhou. If possible, you could purchase the train tickets one day in advance which will save more travel time for you on the 2nd day.