"Hey, these are "SM" quality calculations."
Well then, I guess SM has improved his math:)

"A trivial comparison with Apollo figures shows gross understatement of mass and overstatement of capability at each stage of the process."

In a "trivial comparison" Saturn V did lift far more than two Protons or two Titan IV- almost 3 times the amount. Saturn V: LEO Payload: 118,000 kg. to: 185 km Orbit. at: 28.0 degrees. Payload: 47,000 kg. to a: Translunar trajectory. Whereas the largest booster available today lifts around 20,000 kg to LEO.
But as I have posted before and given various references, it's quite possible to get crew to the Moon [and back] without requiring a Saturn V class booster- whenever I'm talking about going to the Moon for 3-4 billion that's what I'm talking about. If we needed a Saturn V type booster it would cost tens of billion to go back to the Moon. Basic ref: Gemini to the Moon:
http://www.astronautix.com/articles/bygemoon.htm
Above link describes a similar way of getting to the Moon without a Saturn V: "Right up to the end of the Gemini program, the Gemini spacecraft was considered by its contractor and certain factions within NASA as an alternate means of reaching the moon. The Gemini re-entry capsule, smaller and lighter than that of Apollo, would allow direct launch of a mission to the moon using a single rocket. Alternatively, rendezvous and docking of components launched by two small rockets (Titan 3C's or Saturn IB's) would eliminate the need for development of the Saturn V." We curently have "Titan 3C's or Saturn IB's" class boosters such as: Proton, Ariane V, and Delta lVH (or Titan lV which are being replaced by Delta lV and/or Altas V- which will lift more than Titan lVB).
Now, you probably can't get to the Moon if you use something similar to Apollo Lunar Lander: "Total Mass: 14,696 kg. Total Propellants: 10,523 kg. Primary Engine Thrust: 4,491 kgf. Main Engine Propellants: N2O4/UDMH. Main Engine Isp: 311 sec"
http://www.astronautix.com/craft/apollolm.htm
One way to improve it is to use a different and higher ISP fuel- at least in the descent stage. N2O4/UDMH is pretty good if you want a fuel easily storable, but LH&LOX gives much higher ISP (450)- and ISP is "everything" if you want to lower mass of the vehicle. Storing LH&LOX for 3-4 days is not too difficult (don't lose much by boiling off to keep LH cold enough). In other words if you just take the Apollo Lunar Ascent stage: Overall Mass: 4,547 kg, and try to solve how to get it to the surface (without using Ascent's fuel) can "start to see" how you can do this.
But 4,547 kg is still too much mass for the Ascent stage. Now, there are various ways of decreasing the vehicle total [LH&LOX would roughly half it's mass, but then you got problem of keeping it cold, but there are other fuel choices which might give better ISP and be easily storable]. You can also reduce the weight of structure- such as one passenger, open cockpit, no cargo capacity, higher acceleration, and using rocket stages.
So, if you reduce weight of ascent vehicle, you can dramatically reduce launch payload. Personally I favor reducing ascent vehicle, by not even bringing it with you- land ascent vehicle on lunar surface before crew goes to the Moon. Also preland "everything" crew will use- place to live, tools, supplies, etc. If "all you have to do" is land crew on the surface of Moon, it's pretty easy- could use one Delta-lVH (assuming it was manrated) and launch them from Earth surface to lunar surface- without docking other payloads (or going into) LEO or lunar orbit. One of the many problems with this would be the abort option (you wouldn't be carrying your earth return vehicle). Nor is Delta-IVH manned rated (first launch, I believe, is this year- and at this time no plans to be used for crew launches as far as I know).
Anyways I wouldn't use just one Delta-lVH, I would also use some vehicle which was manrated (Shuttle or Soyuz- and since I'm thinking of a NASA mission without Russian involvement that would limit it to the Shuttle). And crew would go to Moon with the Earth return vehicle.