I made a spaceplane with a tantares lander in the cargo bay on a moving docking port. This allowed for much easier docking and releasing of the lander. I went to duna and back both on sub prime transfer windows. On kerbin orbit I had over 9000 delta V. Made it back to ksc on fumes
Mods used:OPT, Tweakscale, Fuel switch, Tantares, adjustable landing gear, lithobrake, infernal robotics, and Mechjeb