I am taking on the task of insulating our 1946 house. I am in the process of removing the wallpaper in the dining room and figured since I am going to be filling in holes to prepare the wall I might as well look into insulation. The room has one exterior wall, 2 interior and one facing the unheated garage. Should all walls be insulated? What is the recommended type of insulation for behind these plaster walls, foam or blow in insulation? Any tips for install?