You will need Mechjeb (2.5.4.0-521 or newer) and Mark IV System (2.0.0 or newer) (http://kerbal.curseforge.com/projects/mark-iv-spaceplane-system/files/2248802)
This plane should be able to fly, land and take off at every spot on kerbin or it carries much payload for midrange....or many variations in between.
It should be able to be mounted onto a rockets tip as well (untested so far)
A mix of one pilot, engenieer and scientist should be on board.
One kerbal (scientist) can be dropped in a capsule attached to a parachute .
And you can drop for him two rovers on parachutes as well. This has to happen in the air, otherwise the rover wheels will break on impact.
So practically you drop everything with a speed slower than 250m/s and above 1000m altitude.
The plane comes with less fuel and oxidizer than its able to carry, because it will be more comfortable to fly as a VTOL.
Button 1: vertical engines (on/off)
Button 2: horizontal engines (on/off)
Button 3: horizontal engines (switch mode [Fuel-Air/Fuel-Oxidizer])
Button 4: cargo bay (open/closed)
Button 5: ladder (retract/extend)
Button 6-10: you can edit those for the best setting of your experiments
Take-Off-Scenarios:
1: pure vertical start: Button 1 + T (SAS) + R (RCS) + Z (full throttle)
2: diagonal start: T + Spacebar + any throttle equal or higher than default
Have fun to test with it. I think, ill come up with more helpful versions and/or addons