Body part splits are not necessarily more intense than full body workouts. Intensity is determined by percentage of max. Splits of all kinds may be extremely intense of very "unintense" depending upon what you decide you are trying to accomplish that day and what set/rep/weight scheme you use. What body part splits do allow for is to get more volume for the muscle group/groups being worked in that particular workout. However, over the course of the week or longer,over the course of a program, there may be no difference at all. If I do 12 sets of chest on Monday in my body part split and I do 4 sets for chest on M-W-F, I still do 12 sets for chest over the course of a week.
Better results is 100% tied to goals. I'm sure I could get better cut calves following a bodybuilding type split, but I'm equally as sure that I will get better relative strength numbers on my bench, squat, and deadlift following a max effort/dynamic effort/repetitive effort type program.
Body part splits, Full body workouts, upper/body workouts, push-pull splits, push-pull-legs splits all have their pros and cons depending on an individuals goals, needs, and enjoyments.
Alwyn Cosgrove, Chad Waterbury, and Christian Thibadeau debated this topic a few years back on T-Nation.
Part I
http://www.t-nation.com/readArticle.do?id=1333967
Part II
http://www.t-nation.com/readArticle.do?id=1335480
Now, Cheryl appears to really enjoy lifting, so the challenge is to come up with a split that allows her to train 4 or 5 days per week like she wants to do. Wheter that is a 5 day body part split, a 4 day upper lower split, a push-pull-legs split using an A-B-C-A 4 day set up, or something else entirely depends on her other goals, the other components of her total training program, and her nutrition.