I've tried to track down a very similar-sounding, and equally obscure game in the past - it might be what you're looking for as well.
The game is called "Dark Tower", and is about exploring King Arthur's abandoned castle. There's some text-based entry ("U SWORD"), and some action (press "W" to start walking forward, space to jump). I played on the Apple IIe as well, although I believe there was also a C64 version.
Picture of the starting room:
Picture of jumping over stairs - the top half of the guy is missing due to my poor timing with the screen-cap software. Jumping was very flickery (although it doesn't matter, since you have no control once you've jumped)
There's at least one other game with the same (very generic) name from that era. This is the one in the "
Twistaplot" series.