It's actually really hard to get a stable lunar orbit. The reason is that the moon is of uneven density. The lower the orbit, the harder it is. It turns out we had our first sattelite orbit the moon for a long while only by luck. Only special orbits will be fairly stable, and the orbit of a space station (meant to last a while) would have to be adjusted frequently if we plan on having it pass over a specific region frequently.

I'm not saying it's impossible, since I don't work for NASA. But low moon orbit below 100 miles is probably never going to happen, due to the impossibility of rescuing the station if its orbit changes more quickly than expected.

You wouldn't need a very strong ship to travel to the ISS and this LMO and back, because at either one you are pretty close to a place where you can escape the earth or the moon. The hard part is, creating a ship that is made to travel from space point to space point, which currently doesn't exist.

A Space Station in Low Moon Orbit is perfectly Feasible. If it is to be placed in one of the five libration points also known as Lagrangian points .These points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite or in our case a Space Station , with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to rotate with them. They are analogous to geostationary orbits in that they allow an object to be in a "fixed" position in space rather than an orbit in which its relative position changes continuously.

So as you can see from the foregoing it will be in stable orbit and not only that but also the costs in terms of fuel consumption will be next to nil, thanks to the gravitational canceling effect of those two large bodies. I my opinion the vessel to be used to facilitate transportation between the ISS and the LMO Space Station, would be more along the lines of the docking shuttles that are currently being used to transport personnel and cargo from Earth too the ISS.

For the more technical definition of what a libration/lagrangian point is then here we go.Lagrangian points are the stationary solutions of the circular restricted three-body problem.1 For example, given two massive bodies in circular orbits around their common center of mass, there are five positions in space where a third body, of comparatively negligible mass, could be placed which would then maintain its position relative to the two massive bodies. As seen in a rotating reference frame with the same period as the two co-orbiting bodies, the gravitational fields of two massive bodies combined with the centrifugal force are in balance at the Lagrangian points, allowing the third body to be stationary with respect to the first two bodies.

As a matter of fact NASA and the ESA have been conducting precisely the kind of experiments you are asking about with some measure of success. For more information check out the sites below and you will thank Sci-FI Authors who wrote fictional accounts of such things happening some 150 years ago, little believing they would come to pass. I hope these information is helpful.