If you want to be a skipper, yes, a USNA tour is stepping off the Golden Path. People have done it and stayed competitive, but when following tours are described as "get-well," that pretty much tells the story.
However, if your idea of a successful career is doing a challenging and rewarding job, and getting promoted and paid in the meantime, and going for 20+, then getting on the Academy JPMP/PMP track is not a bad deal. Go back to Naptown as a LT and conceivably never leave again until you hit retirement as an O-6. Get a second master's or doctorate in the bargain. Of course, there are a lot of dudes vying for spots as JPMPs.
I would not recommend going for a Dant's staff job, or sailing or leadership instructor, or something like that. Takes you off the path but doesn't really buy you anything for a career Outside, either.
If it's advice you want - don't talk to the detailer or your front office about this until you've got your good paper. JPMP, which is what it sounds like you're interested in, is not a billet you get detailed to. You apply for it and are selected by a board. A smiley-face final competitive fitrep will help a lot. And if your front office is like every other one I've ever heard of, once you tell them you're going or want to go to non-production shore job, you just made their "who gets the MP" decision process a lot easier. It's not vindictive...it's just thinking why should they waste 'competitive' paper on someone who's not competing? And if you change your mind about USNA or aren't picked up, you've blown the bridge before you crossed it.