Yeah, essentially its a return trip lander mission. Or, how far can away from Earth can you be to get back from the surface of somewhere else on a 90t tank.
Best thing is, you can use anything you like to land it there, so it'd be a case of sending an entry from the single tank to orbit/single tank to the moon challenge as a payload of a larger rocket, placing it anywhere you like and flying it back fully fueled.
With ion engines, it's entirely possible to get back from pretty much anywhere with 81t of fuel. Hell, you could do a reverse flyby grand tour and some choice landings and still make it home.