For the record, it actually makes a difference here if your moon is a Blood Moon or a Magus, because a Thoughtseize on a non-Chalice play is much more devastating to your hand if your only threat is the Rakdos Pit Dragon. On the flip side, if you have a Magus, you can drop it as your second play after the Chalice-1 and have it STP protected, which will make up for the fact that you may take awhile to drop your RPD.

That said, I agree with Phantom and would lead Mountain, Go. Your hand isn't strong enough to risk leading with the City.

I disagree with the second play, though. Leading Mountain, Go here gives you options based on what your first draw is and what your opponent plays. Your turn two play will most likely either be a Trinisphere timewalk or the Moon, and at some point you'll get your Chalice for 1 down before emptying your hand and getting your Dragon on the board.

It's also an option to make your turn two play Mountain, Chalice-1, if you don't draw a mana source and see no indication of a possible Daze on your Chalice. The plan at this point is to protect your manabase and try to get your Dragon down before your Moon, to make sure you hit a fourth source.