We have three central A/C units, electric everything (fridge, hot water, etc.). We could be fine in an emergency with one A/C, fridge and just some lights... we can cook on the outside BBQ grill.
It would be nice to keep the pool pump going during a 3 week outage otherwise the water would probably need to be completely replaced afterwards, which is a cost.
Hunn...I would search for a used CAT unit. That said fuel consumption is a big deal. If you don’t have power chances are your supplier doesn’t either and if the roads are a mess then getting fuel delivered is a big problem. Storing a large amount of fuel is also a problem. Propane is the worst bang for the buck and diesel is the best.