Thanks to all of you. I realized after I posted this thread that I basically had what we've always called a Prime Rib Roast without the ribs.
After reading countless recipes and reviews I think I'm going with a 'foolproof' method posted on allrecipes that basically calls for seasoning the roast on the outside, onto a rack, then 1 hour in a 375* oven, turn oven OFF for 3 hours and then turn oven back on to 375* for 30-40 minutes to finish cooking and reheat right before serving. It's supposedly really hard to mess up, but we'll soon find out.
The recipe is for a 5 lb bone-in, and I have a 4 lb NO bone. I know that boneless meats usually cook faster, so I think I'm going for 45 minute cook time and then turn oven off. I'm keeping my digital thermometer in the entire time. Some reviewers said that the method was fabulous but there was no real aus jus, so many poured beef broth and wine in the bottom of the pan under the rack and then reduced it on top of the stove.
~ "The right shoe can change your life...."- Cinderella ~