On the orbit mfd display, selecting on the MOD button, should toggle between ApD (Apoapsis Distance from Surface) and ApR
(Apoapsis radius from centre of gravity).
As for extra panels. the addon is the CARM from Niven's SmokeRing. This vessel is a bit of a departure from most Orbiter
craft in that it runs on water. More specifically, it's propellant resource is water. The water is electroyzed into its
constituent hydrogen and oxygen (for reaction products) through an algorithm dependent on your distance from the primary
star. The exterior of the craft is covered in photovoltaics, to provide the power for the electrolysis.
The extra panels come in for the control of the photovoltaics, control of the electrolysis, and better control of the life
support system. It is presently at Beta .5 level and has not been released.
Physical characteristics of the craft: roughly brick shaped, 32m long, 10m beam and 4m in height. The Cabin is VC and since
it's my first attempt at that, it is taking some time.
I think I have more fun in developing craft for my own uses in Orbiter than I do in playing Orbiter.