That'd probably work. It would be interesting, you could say, have the RCX in charge of controlling drive motors, leaving the RC free to determine where you want to go, etc. I have a Mindstorms set (plus all of the expansions (a few of them twice

)), so I might find this and interesting thing to look into.
--EDIT--
Oh, yeah. NQC is good, but BrickOS (former LegOS) is better.

BrickOS is also C/C++ programming, but everything is precompiled, not interpruted like with NQC and the default LEGo firmware.