You're probably going to have to calculate your amp draw. Get a list of everything that'd be running during the day while you're away(pumps, fans, etc) and figure out the total energy usage of that. Then figure out how much power your night time light usage will be.
If your lights aren't LED, I'd recommend replacing them with LEDs.
Then you can figure out how much solar you'll want. But if you're not using refrigeration and can get on all LEDs, then you probably won't need much.