Hi, Fitmom, and welcome too!
"SJP/SB" stand(s) for "Step Jump Pump" and "Step Blast", which are on one DVD from the Body Blast Series and sold as separate videos on VHS. I believe the Body Blast Series is the last series Cathe offered both on DVD AND video, so if it's videos you're after you can get them individually.
I agree with the suggestion about those two workouts as well as Low Max, which is only offered on DVD. You may also want to consider doing a step warm-up with another workout, and only doing the step segment of MIC. The first 35 minutes are increasingly high-octane floor cardio, I know, and can really pummel you if you're new to that intensity and/or are coming back from an illness.
One of our beloved Cathe-ites, "Lunacat", created an awesome Compendium of all of Cathe's workouts through the Hard Core series, and this compendium includes all of the common abbreviations of her workout titles as well as running times, equipment needed, emphasis (cardio, strength, muscle endurance, etc.). I'm sure if you asked her nicely she's send you one be e-mail. If you're interested, put up a post attention LunaCat on the Open Discussion and I'm sure she'd be happy to oblige.
Welcome again to The Cathe Fools.
A-Jock