Don't refuel in orbit - just dock
It's a simpler solution, which can easily be handled robotically (ie, so your craft is completely assembled & tested before you risk putting people on board). Proton, Zenit, Ariane cinque or even the new Atlases could lug large enough chunks to LEO to fly a human Lunar or asteroid mission from three or at most four components without wasting unnecessary funds on advanced booster creation.
Robert