"As just one of the issues you skate lightly over:

First you propose using cryogenic fuels in the Lunar ascent stage because of their high Isp, and acknowledge the storage problem..."

No, I said you could use LH&LOX for descent stage- I think you could do this quite easily. I did mention possibity of using LH&LOX on ascent- but this would depend on details of mission. The manned mission is going to the Moon to confirm the existance of minable deposits of water- which could mean mining some water and possibly converting some of this water into LH&LOX. If you are bringing equipment to make LH&LOX, then you also would probably have means of storing LH&LOX. It *might* also be desirable to mine "sizable" quantities of water and convert it into LH&LOX and use it for rocket fuel (sizable meaning about 2-3 tons of water). Or possibly instead of mining all that water, you could pre-land a couple tons water (or ice). But depends on how much power and time you have on lunar surface.
{Or maybe, you want to test some sort of robotic system for extracting water and processing into rocket fuel and this could test some things out by first "mining" some pre-landed water. BTW that robotic miner thingy wouldn't necessarily be part of a 3-4 billion lunar mission, but if some company wanted to build and test it on the Moon, then maybe NASA could provide money for launch (and that launch cost would be part of the 3-4 billion program)}
[Btw, the manned aspect of mission would come after a fair amount of unmanned exploration of entire lunar polar regions (orbitor, landers, probes, and/or robots]

"Then you talk about pre-landing the Ascent stage.

There is a huge mission risk here. You need to pre-launch the Ascent stage no more than 24 hours prior to the manned mission, travel all the way to the Moon and hope that the Ascent stage lands safely (otherwise you abort prior to Lunar orbit insertion)."

The pre-landed stage would use fuel which was storable- it could be same fuel as used in Apollo ascent stage. {in eariler posts I called this "pre-landed stage" the "emergency return vehicle"- though it could very well end-up being the "regular" return vehicle]. It could be sent directly from Earth to Lunar surface- this would require less delta-v than going into LEO and/or lunar orbit. Also it doesn't need to carry any crew or their life support (this could added by crew when leaving the Moon). Could use LH&LOX for landing the ascent stage on lunar surface. This ascent stage also can use trajectories which might be consider too risky for a crewed vehicle- e.g. doesn't need an abort to earth as an option. You would have ascent stage on lunar surface, and sending back information confirming it was operational before crew left- before they got on Shuttle.
Prior to even the pre-landed stage, you would have a landing site with at least a beckon- perhaps a robotic lander which could give pictures of landing area and serve as communication relay.

"You have to get 2 craft off the pad within 24 hours without any launch glitches. Notice recent Shuttle performance on this detail.

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I think you need to review your figures more closely.

At many points, you appear to willfully misunderstand the way the Apollo mission stored consumables for each stage of the mission in staged vehicles that were left behind when finished with. For example, the Ascent stage had limited endurance for the astronauts - the heavy stores for a prolonged Lunar stay were mostly in the Descent stage.

You just abandoned this. How will replace those stores?"

Supplies for long duration stay (2 or more weeks) would also be pre-landed. You could have an inflatable dome deployed before crew leave on Shuttle. Large solar panels could be pre-landed, requiring crew to setup. The way I see it, the amount of total launch lift of smaller boosters will equal or exceed 1 Saturn V rocket, but you will get more supplies on the Lunar surface for the crew to use, because you can get cargo to the Moon more efficently by having them go separate. For instance, the crew need a manrate launcher to get off Earth- cargo doesn't. Cargo can take weeks to get to the Moon- crew can't. Cargo can be hard landed or use airbags- crew can't. All kinds of added precautions are needed with human crew- a 100 lbs of food doesn't need all these precautions.
You would need to know if all your supplies got safely on the Moon- but that fairly easy to confirm. If they make a crater on the Moon, you can send more. All this before crew get on the Shuttle. You can also use a similar vehicle that get the supplies to surface as crew is using, which means you are "testing out" this vehicle to ensure that when crew vehicle used it is more reliable.