I understand all you want to do is paint the deck so keeping that in mind, here are my suggestions. I like the colour of the wood floor planks so I would keep them like that and simply put a clear wood sealer. A white ramp to match the door would be nice with the gray wood floor. The trellis part at the front can be painted the same grey as the trim on the house. I would also suggest you paint the yellowish trim around the window on the door the same white as the door. I presume there is a reason for the sconces to be so low so I would suggest you replace them with 1) larger ones, and 2) a style that makes them look taller (such a shown below, or for a more modern look, a cylinder shape).