I'll throw in my two cents. I'd have a plan B if it is absolutely clear that the water is raging (i.e. major rains in the couple days before you plan to go).
I think that plan B could include hiking up to Crag Camp on day one, then leaving your heavy packs and going light up to Adams and Madison if the weather is o.k. Then day 2, bypassing Adams and heading right over to Jefferson and maybe Washington, depending on time, conditions and your own status. Based on what you said, don't think you'll make it all the way to Monroe and then all the way back and down in a day.
However, barring raging rivers, you could stick with your plan A and head up into the Great Gulf, and after about 3 miles there's a crossing of the West Branch of the Peabody, I believe on a bridge, but you'll get a good idea of the flow from here. I'd just keep on going to wherever you planned to camp in the Gulf., set up camp and then make your attempt on the Six Husbands. If the crossing over the Peabody right at the beginning of the Six Husbands is too rough, then you have a couple options. You could turn around and head up the Wamsutta trail to the Alpine Garden Trail and Washington (and then back). Or, you could head back down the Great Gulf trail a ways (depending on where you camped) and head up the Madison Gulf Trail to do Adams and/or Madison and then down the Osgood and back to your campsite. I think I'd opt for the second choice if you can't do the Six Husbands, and then the next day try again (if the water is receding), or do the Washington via Wamsutta option.
Good luck and as long as you remain flexible I'm sure you'll get in some great hiking unless the weather is truly awful. And even then, you could change your plans and do some excellent hiking in areas where your exposure above tree line was not as great as the Northern Presis.