I did this about a month back and found that it is actually pretty easy. I do have a few reccommendations though.... Buy a wireless remote/harness. Then you don't have to bother running wires through into your cab or mounting a switch. Also, you can program your remote to your garage door opener for a cost of around $50 CAD. It was a no brainer to me.
As for mounting the light, I just drilled holes in the cross braces that are behind the grill and mounted to that. The light I bought was a curved 33", and it just happened to line up perfectly to the spot in my grill.
Taking off the grill isn't actually that hard. I just watched a youtube video and had it off in less than 20 minutes. 4 bolts on top, 2 on either side by the wheel well, then 4 underneath (2 of those are a bitch to get at). I've had it off twice now, so its getting easier.
Hope this helps.