I've watched a lot of D3 institutions, their games, practices, and so forth. Mostly on the East Cost and Mid Atlantic, some just below the Mason-Dixon Line.
From what I gathered, these clubs seem to thrive on a program that orbits -the simpler the better. Their overall scale of economy, player pool, etc. doesn't lend itself to the dynamics of a larger organizations. Therefore, your itinerary may be a bit ambitious. I would suggest getting your feet wet first with who and what you're dealing with. Who has the biggest bark among the other coaches and what was the track records of those that went before you as pitching coach.
On the other hand, here's what I've noticed about the clubs in your line of work:
-There seems to be three or four really good players that the entire club revolves around.
-Resources are sparse, very sparse. Fund raisers are a constant way of life and be a bit haphazard at times with people showing up to help out.
-Don't be surprised if you other duties are field maintenance, academic tracking, interfacing with local police, security details, EMT's - at home and away, motel accommodations, meal plan selection and the types of meal plans being purchased by each player while at college, dealing with clubhouse politics, and other assigned details.
-Other programs like "clubs" seem to draw on-again/off-again players and interest. I've seen the "socialites", mostly females, are the main draw here.
-Friends and friends of friends can be a distraction at practice, at home and away games also.
-Although not every D3 program is small, the complexion of the baseball program can be. Unless baseball is a big draw, you might find yourself alone a lot, I mean very alone.
-I found many, and I do mean many, small programs have one or two alumni that were once the top dog in the baseball program. They can pop up once or twice ... sometimes forever, and literally take over your spot with speeches, on field appearances in the dugout, and even drive the bus to and form away games. These guys can be impossible to shake off and ignore. I've seen some that even undermine the very authority that the coaching staff (of two) are trying to maintain.
-Big check writers will have their relatives on the roster, regardless. Just make sure your not the reason for failures or the butt of jokes when they crash-n-burn.
-Religious colleges and such at your level of competition will have, without exception, a built in patronage system that will excluded you from just about every major decision if you're not part of the system by residence, relatives, same religion or social persuasion.
-You will be sharing facilities with other sports so make sure your schedule is included early and all inclusive to what you need.
-You mentioned that you have 20 pitchers - don't count on it. Be very flexible to eligibility requirements as the season progresses - grades, conduct, and so forth.
-You might require a tutor system to help some players. If there isn't one in place for your athletes, start one of your own. If you share in a tutor system, be very selective here. Pretty girls will do nothing for your plans and will only be a distraction.
- And last but not least, internal relations are a very important part of any sport's program - HOWEVER - you're only the pitching coach, DON'T overstep your boundaries here. Be mindful of what your authority is and is not. Remember that you're the new kid on the block, so you have a certain "time-n-grade" to endure. Stick with pitching and don't offer anything outside that realm of business.