To maximize your time in Paris, I might suggest the hop on/hop off bus, as two days is very little time to enjoy the city. L'Open Tour bus will provide you with a great overview and is equipped with an audio guide. If the bus is crowded (no seats on top), be patient and stand at the top of the stairs and kindly wait for a passenger to debark, availing a seat to you. You can catch one of the busses right on Champs-Elysees near the hotel. You can purchase a ticket from the driver. A two day pass is only about 1 or 2 euro more than the one day pass. You can get on and off as you desire, but be mindful of the time table (last stop is around 7pm, depending on where you are. The green line, the grand tour takes about 2 hours and is a great way to get an overview of the city.
For the short time period that you will be there, may I suggest
There is some nice dining right on the Champs-Elysees, but I enjoy dining on Rue Marbeuf, across the Champs-Elysees from the hotel. Chez Andre, Le Relais d'Entrecote, Chez Clement Marbeuf, and also a couple of good Italian restaurants on the right side of the street near the end of Rue Marbeuf are good.
Enjoy your trip.
As far as elite benefits, if you are a cash customer, you might garner a room upgrade. In my experience, points customers with little exception, will only receive a room upgrade with cash. Because you're going in May however, I would not place high hopes on it. Do ask however. You may get lucky. You are entitled to a free cold buffet breakfast. A hot upgrade can be added for 8€.