Suppose we do succeed in establishing a permanent lunar base. Its very likely that soon, the scientific or commercial possibilities of the place will be exhausted. What do we do then? Pack up and leave?

I would prefer that whatever forward base we do establish in the solar system will be available indefinitely for other projects and expeditions. IOW, it should be a facility that can be updated and expanded for staging future exploration programs. Of course, no one can say for sure if there are or are not valuable resources on the moon that would make a permanent base there useful. But the same can be said for any place in the solar system. Do we really want to start an expensive prospecting program in such a hard to get to place?

I would suggest a recon stop to establish whether or not ice can be found there to determine whether mining it for fuel and oxidizer is practical. Remember, even if it can be proven that there are vast pockets of water ice in those polar shadows, will it be practical to collect it, purify it, ionize and cryogenically store it for future use? This would involve transporting and operating a nuclear or solar powered refinery and storage facility to the lunar surface, and to supply (and relieve a crew) to man it.

I would rather see the same effort put into establishing a permanent space station at one of the Lagrangian points where fleets of heavy-payload ships could be assembled and fitted for missions to Mars, the Belt, or even the outer solar system. There are plenty of moon-sized worlds orbiting the gas giants, not to mention lots of water ice floating in free fall, ripe for the harvesting...