UltraOne

Below is an image of the setup I used when I wanted to get a Kerbal into a command chair (the vehicle is for Scott Manley's minimum time to space and back challenge). The blue arrow shows the path the Kerbinaut travels on the ladders to get to the chair. Once he is in it, I trigger the marked decoupler to drop the Mk1 Lander Can onto the launchpad, where it is left behind.

I agree with the many comments on this thread that Kerbal XP should not affect parts of the simulation the player has direct control over, such as anything having to do with vehicle flight performance or piloting (e.g. thrust, ISP, heat generation, turn torque). The fact that this would mean that the viability of some designs (to reach orbit, for example) would depend on crew XP is a further reason not to do this. I am fine with Kerbal XP affecting things that are already abstracted, like science, money or reputation rewards. I am also Ok with a system where Kerbals have AI that allows them to complete certain tasks (e.g. docking) automatically, and the XP determines how rapidly and efficiently (in terms of propellant, for the docking example) they can complete the task, as long as none of the physics rules in the simulation are broken.