If you have worked on OTR rigs and done some frame drilling, it should be an easy project for you. My biggest concern is that you have enough room for your drill motor to be able to hold it square (horizontally).
I would measure twice (actually for me about 4 times!) Use a punch to mark the spot, drill a pilot hole and use a good split point or equivalent drill at slower speeds.
Good luck and have fun!
That was an excellent buy, IMO
'97 Country Coach Intrigue