Yeah I hooked and inverter up to my car and ran it off of the battery
whenever I have power issues. I lived in SF when the power was out for
6 days and once my GFI recipticle went bad. I was only able to run the
essenatials due to the inverters limitations but it got me through it.

A UPS is not always a good idea since the draw of pumps and various
equipment can change and trip the UPS on power surge. The APC 1500 VA
would be the only one I recommend since it can be eaxpanded to 3000VA
with the extra battery pack.

If you are looking for the long run a small geneterator is the most
reliable and longest running. Honda makes the cheapest, quietest, and
most effiecent for its size.

If you are looking to have an ATS (automatic transfer switch) that is a
good deal more work and requires an experienced, liscenced electrician
to install.