Taking "Time Off" - How Long?

You did Philly recently, so really want to have 3 - 4 weeks to fully recover from that.  For myself, that would have been adequate time to "recover" and get ready for the next year.  I basically did that after Baltimore in October and have just sort of been futzing around doing a little bit of this and a little bit of that, but keeping up some sort of consistency so I do not fall off too much.

Are you using a specific plan for E-Man?  A 24 week one would actually have you starting soon for that (January).  An 18 would not be until later.  If it were me and you do not have any intermediate races you want to hit well at, I would have you working on your limiter right now (whether that is swimming or cycling .... with marathon training under your belt, it is probably not running) as the main focus with less sessions in the other two.  That way when you roll into whatever plan you are using you will not be starting from scratch.

There are some coaches who prescribe ZERO organized work for anywhere from 2 - 5 weeks.  I think that really is an athlete-dependent thing.  If they had a huge season with a lot of intense work, then time off completely may be in order.  But if they were just consistent through the year with a few races here and there, then there is a better chance they can continue at that pace of training.

Do yourself a favor, dump the weights and use that extra time in the water.  The weights will not gain you a single second on race day.

And get one on one sessions with a coach to work on your form.  Being in a Masters program is great for getting in the yards and speed, but with limited coaching time you may still be swimming with less than stellar form.

At least those are my opinions.  Good luck in your quest!  I'll see you there on race day (4th year of doing the race in a row)!