I am loving the idea- I can never find anyone to D with, but I have to agree with the river or summit idea. Even in river or summit I have trouble finding people sometimes, but getting those random invasions is worth it. Especially when you're trying to get 14K JN's, it is awful when you see how little you get if you finish without the invasion.
The past 8 CJ runs I haven't gotten an invasion summons (maddening), so I think you'd be hard pressed to find that many toons with invasions that are going to do D runs when you need them. Even in summit, invasions happen relatively frequently, and I can NEVER get on river (lol) so I'm all for the summit idea.
Edit: To get 14400 JN's, you only have to do a D office 9 times. Without invasions you'd have to run almost
16 times. OUCH.