High Power Supply over a distance
You can use a higher frequency than the standard 50 or 60 Hz to reduce the volume and weight of the transformers (for example the aircraft industry use 400 Hz as the standard in airplanes).

Personally I'll don't go beyond a few kHz to avoid all kind of problems but it's just a rough estimation (and you might need a higher frequency than that to pass 2 kW with a 2 kg transformer), do the math to be sure. Also, if the frequency is relatively high for the wire thickness, think about using litz wire for the transformers windings, you lose on the volume but you win on the weight.

To drive the first transformer you can use a H-bridge (or even just a half-bridge with a center tapped primary on the transformer) and a crude astable since the efficiency isn't a concern. You can do better by approximating a sinus with multiple taps on the primary but it gets far more complicated.

On the other side, after the second transformer, just be careful about the switching speed of the diodes if you want to rectify the current (classic rectifying diodes might not be fast enough), use schottky diodes if you want to be sure to have no speed problem ever.