Just did the same thing to my 4310 - sort of. I bought the light kit from Deere for $60 bucks I think (normally more then I would spend). However, the tractor is already prewired for the Kit - you find the connectors near the three point arms and simiply plug in. So I took the easy way out. However, pulling the wires thru the rops looked like a nightmare, so I ran them thru a clear vinyl hose on the outside of the rops and zip tied them to the rops.
One other thing, since I see your backhoe setting in the back ground... I have a habit of working past dark digging with mine, I installed the lights almost at the top of the rops. This way they are above my head when I am in the backhoe seat, if I turn to look off the tractor I do not get blinded, they also actually do a pretty good job lighting up the hole.
My two cents worth...