Beg to differ with your beg to differ. That's not a prime rib or even a prime rin, that's a full rib primal which is something else. The everlovin' IMPS 103.
Plus, as a practical matter she needs a lot of trimming. She's totally unequipped to deal with the chine -- rather removing it or cracking it. The feather bones are as much of a challenge as she can handle and she'd be better off without them.
The fat cap isn't going to do her any good either. While you, Old, foodpump, I and a few others might take the cap in one piece, cut out the false lean and fat channel, season the lip, and truss the fat back on -- she isn't going to because she doesn't know how. She should get a 6 rib "prime rib," with the fat cap, false lean, fat channel, chine and feather bones all removed. In other words, ready to season and carve. I forget the IMPS number, something like 109D or 109E.
By the time her roast is all trimmed out and oven ready (none of which she should be doing herself) the weight is going to be something like 15 - 18 pounds. Don't blame me, it's the truth.
FWIW, I don't consider not knowing a bunch of fancy butcher stuff any more of a handicap than knowing how to do fancy sugar work. Nobody knows everything. We all have our strengths. Mine just happens to be cocktails.
Not shtirred,
BDL