your plan is fantastic! it's all i0ve dreamed for when i bought KSP! Really, no joking... And i will love to take part of the project and give some help, if i can. Especially the "mission design" part. About the mod, why not to implement the realism overhaul? With the Real Solar System (and FAR), your idea to develop an interactive campaign will be perfect, because a single person simple could not really manage all. The best would be like this: one person design the mission (in general, so like: manned landing on the Moon; in particular, so the delta-v/TWR and all the "numbers" of the mission; and the budget), another person design the payload and the ship and finally another one actually fly it. (sorry for the bad english...)