the sheraton in pattaya is really nice. it is not that difficult to get to and once there you are fairly insulated from pattaya unless you choose to go see the sights. if you want minimum additional travel this is a good option. as to going wednesday night when you arrive, i am not sure i would start a 2 hour car journey in thailand at that time of night. spend your first night in one spg property and then you last two at another and you can see two parts of town.
for the first night maybe the westin or the sgs ( i like the sgs ) and then for the last two days the royal orchid on the river or the new le meridien which is fairly central.