Cavtrooper,
Time on the mound between outings is very important. Not only is it a time to work on new things but its a time to forget about the bad things. The bullpens do not need to be at 100%, especially this time of the year. I would keep it to one bullpen session between starts/outings with the focus being on maintaining a good feel for pitching. Not sure if you golf but think of it as time on the range. Get some kinks out, work on stuff, forget stuff but overall just trying to keep the feel. If a mound is not accessible between starts then work in a "flat ground" routine into the throwing program. Have his throwing partner squat for about 12 pitches after warming up. Keep the distance short and the velocity at 60%. Pitching mechanics are just like a golf swing. You never figure it out, you just hope to maintain?