I salute you for the idea--it's the sort of thing I will always attempt, no matter how inadequate the support--but despite some heavy Moat and Watchtower defense from Witches, I still think the Silk Road plan is in trouble. Other than Duchess/Duke and Crossroads, you don't have anything to really aid a Silk Road plan. There's no extra buys to get free Copper, no gainers. And those Curses actually do really get in the way of Crossroads.
But... I don't know, if you had gotten a more favorable Silk Road split, then maybe. But if you go for SR too quickly, you don't get your Duchy/Duchess thing going. Interesting, though.