This solution was provided by Dereck Davenport.

Add this code to the local CSS. Tested in the Major Marketing theme.

/* only print main content */
@media print {
body > *,
#breadcrumbs,
.phone_nav,
.sidebar,
#left-sidebar,
#right-sidebar,
#social-counters {
display: none !important;
}
 
body > .container#core-content {
display: block !important;
}
 
#core-content > div > div {
border-top: 0;
}
}