It seems like Whitmore is in cahoots with Mrs. Hawking. . . .an Whitmore obviously seems to think Ben is bad news. . . . so why would Mrs. Hawking not raise an alarm when Ben showed up on her doorstep and keep him from the island?

They both want the same thing perhaps... John on the island working for their own side. Hawking knows John needs to be there, as well as everyone else. All she cares about is getting everyone back.

Why would she help Ben get back? Is Widmore the only one who thinks he's a creep?
Maybe she knows he's going to be back anyway, so there's no point in trying to stop him.

They both want the same thing perhaps... John on the island working for their own side. Hawking knows John needs to be there, as well as everyone else. All she cares about is getting everyone back.

This seems to be the case to me. Everyone, regardless of side, needs John back and probably all of them back on the Island.