Then Earth-Moon L2. And we are, in fact, building a space station there. We have the rockets and capsules to get folks and equipment there. Or will within two to 5 years.
The NASA plans to build the station in Earth-Moon L1, which is between Earth and Moon, not in Earth-Moon L2, which is behind the Moon looking from the Earth.
Earth-Moon L1 though would be a pretty good spot to park probes ready to launch pursuing a comet though.
Technically, the orbit baselined for NASA's Gateway is Near-rectilinear Halo Orbit, which is a particular class of EML2 halo orbit that happens to loop around the Moon... ...and it is chosen partially so Earth is never eclipsed (unlike many other EML2 halo orbits). EML1 is no longer baselined.
