Congrats to Murray and his fans. He has a very, very doable chance to reach #1 by the North American hardcourt summer because of Wimbledon. Novak's game has coincidentally and seemingly taken another lower level wise when you compared it to this time last year which obviously still pales in comparison to his record season in 2011.. Not saying that is going all down hill for Novak, but he did drop a level last year and it seems to have perhaps continued a little for this first half of the season.
Either way, if Murray can gain points on clay and do very good on grass which really if Federer is out of sorts then he could coincidentally be the favorite to win Wimbledon this year, he should be able to pick the number 1 ranking up.
If Djokovic was to get Nadal or even a Del Potro playing well in the clay masters quarter finals, he could lose an absolute chunk of points.
What Muzza has to do is play Queens and win it, Wimbledon will be decisive. Whatever happens there will define his chances. If he defends his points or even wins (I don't see anyone to fear bar Nadal who on slow mud in week 2 is a monster to take down) then he has to make sure he can cushion his Olympic points drop-off with 2 good weeks at Canada and Cincinnati.
All ifs and buts though!