jwatte:
Why are the 750k and the 250 ohm resistors in parallel? That will just waste your energy.
You should use the calculated load of the circuit when on instead of the "250 ohm" resistor.
You should use the top resistor to limit current draw while charging.
The 750k resistor seems totally useless -- current will be drawn by the capacitor when charging, not by anything else.
The 750kohm and 250ohm are just emulating my real circuit parts, specifically an ATmega328P in power-down mode (4uA with watchdog enabled) and a radio module that's doing 12mA in TX mode.
Sorry for the confusion. I couldn't draw them in the simulator, so I just drew their equivalents (so-so).