Susie-Q, if you like it medium-rare to medium, smoke it at 200 until internal temp is 128-135 (depending on how done you like it. I find prime rib perfect medium-rare). Let it rest for 30 minutes, while your oven heats as hot as it will go. Put your roast on a baking rack in the hot oven for 7-8 minutes to brown the outside; this is called a "reverse sear."
Check out the link to Christmas prime rib, posted in my first post above. This explains the low/slow/reverse-sear technique for beef. Works great!!