Rook-Level Chess is a very nice idea. Of course, the Queen isn't
R-level...
As for K+ND versus K, confining the K is tricky but it can be done.
Example: BKb8 WKc6, White ND e4, Black's move 1...Kc8 2. Nd6+ Kb8 3. Kb6
Ka8 4. NDc8+ Kb8 5. NDc6+ and 6. ND a6 mate.