Rats/Watchtower is a really strong opening, also in this kingdom.
On the second shuffle I'd want to get another rats, another watchtower and a worker's village.
After that trashing should go fast. Id you're lucky you can skip silver but getting it is not that much of a problem.
This opening does delay hitting $5 yourself a bit, but on the other hand - I'm not scared at all by the $5 cards with that deck.
Margrave even helps, Ghost ship doesn't hurt as long as you have a watchtower in hand.
Even if this delays KC by a turn or so (and I'm not even sure it does), the trimmed deck should be totally worth it.