When you do become that civilian captain and you want to go training, the world is your oyster. If you fancy night mountains then fill your boots. There has never been a restriction on what you can do taking all the calculated safety into consideration. After all even the MOD doesn't accept training incidents/accidents these days.
At the moment the current civ bases have crews with 1000's of hours and on averages a few hundred missions under their belts. Convincing them to participate in worthwhile and essential training has never been a problem.
