Beginner10,
Two summers ago, my DH, father and friend, drilled holes in our wood siding and filled our 100 year old house with blow-in insulation. They filled the attic first then drilled holes for the walls on the outside. Blew in the insulation, filled the holes with plastic plugs and then put the vinyl siding back up and no one was the wiser. Your house will be so much warmer and you will see a saving on your heat bill. There is some mess involved but well worth it. Good luck