I wouldn’t cut out all Cardio since you will lose endurance faster than you lose strength. How much and what type of Cardio you do really depends on what you can handle and still recover from for your next workout. If you find that it’s hampering your recovery, most likely when things get heavy, then you might want to cut back but I wouldn’t drop Cardio completely.
If you are going to do HIIT and Hill Sprints I would probably do them right after your HST workout or alternately do an AM/PM split between HST and HIIT. Slow Steady State Cardio could be done any time but there is evidence that when done right after an HIIT style routine you may burn more fat.
Keep in mind that if you do include Cardio then you’re going to need to increase your calories to account for it to ensure you are getting enough to grow.
Male: 51 years old
Bench Press 240 lbs. @ 178 lbs. (12 July 2012)
Power Squat 390 lbs. @ 180 lbs. (10 November 2012)
Deadlift 390 lbs. @ 180 lbs. (27 November 2012)
Total 1020 lbs. (finally made it 16 July 2012)