Ovinomancer said:
Part three: Liberation
The idea of using earth elementals to tunnel into the city is a good one, but limits the amount of troops you can bring to bear in a short time.
I said -many- earth elementals
City is on a cliff, right? Hollow that sucker out!
My mental image was of hundreds of huge and elder elementals bursting out of the ground and the 70,000 troops I told them to get earlier (which they don't need now, but why not be thorough?) pouring out after the elementals and unleashing all hell on the unsuspecting bastages.
However; enough clerics to PA or GPA in some huge earth elementals long enough to dig a tunnel as wide as a football field -and- fight afterwards might be tricky. (And expensive. Greedy Clerics.)
Having a skirmishing force to distract attention while hell boils out of the tunnels is a good idea; but if 10k in men is all you can muster I'd scrap that plan. You'll die. (a -lot- of their troops are worth 10 men side by side, much less on a wall.)
That leaves sneaking in to steal the thingamajig-ultronicus-maximus. I wouldn't fly in, as there are 4 (i'm assuming) largeish dragons hanging out in the city who would probably love some lunch delivered. (you don't want to deal with 4 dragons while flying at 60. just trust me. *rubs scar*)
If sneaking is your plan, I would go with the tunnel option; one large elemental should suffice, and I beleive Lesser Planar Ally would work (That means the money-grubbing Cleric costs less). You'd better hit that stony mother with a silence spell every couple hours though; I'd bet that out of 7650 troops, -someone- is gonna hear it stomping around under the city.
Once you're inside, you're on your own. I'd love to come along, but I've, uh, got stuff to drink, coffee to talk to, and people to brew.