I think your solar solution for your pump is a good one.
To be electrically efficient, a DC 12 or 24V would be preferable so that you don’t have loss through your inverter.
If you want to get a bit exotic and experimental on your power source, look into biomass gasification. These things will run a gasoline generator on wood and waste.
http://taylor.ifas.ufl.edu/documents/Handbook_of_Biomass_Downdraft_Gasifier_Engine_Systems.pdf
Nothing really ‘experimental’ about wood gasification. It’s an old and proven technology.