It all depends on what is available to you. At worst you go to a zener diode. In any event experiment BUT regulate. Taking power directly from an oscillator is a sure recipe for problems in many cases. The components in a buffer are relatively cheap.
Mechanical stability has an effect on oscillator drift Rigid construction is of course best.
Components and wiring capable of mechanical vibration are a source of problems in oscillator drift. Well like all things here, aim for the best but live with what you can achieve in the real world. Shielding and heat sinking I've seen oscillators constructed on a base of heavy sheet brass. Mechanical reasons and to conduct heat away as much as possible. I've even then insulated it by gluing pieces of styrofoam to it.