Having lived in an area prone to power outages due to winter storms for many years, I can tell you a 5,000 watt generator is more than adequate to get you trough temporary outages.
I purchased a portable contractor-grade generator rated at 8,500 starting watts/5,500 running watts with a 30-amp receptacle, similar to the one shown in picture below.
I hired an electrician to install a generator transfer switch, similar to the one in the link below. The transfer switch I purchased had 10 circuits as the one shown but one with 6 or 8 should be more than adequate for most homes.
I had the electrician connect most of the house circuits to the transfer switch so practically the entire house had electricity when the generator was running. I told the electrician not to connect the circuits with the trash compactor, waste disposal, microwave, dishwasher, and washer and dryer since these appliances require a lot of juice but are not critical during power outages.
With this type of setup all you need is to connect a 30-amp cord to the genny and the switch box and you're good to go. And more importantly, this is the SAFE way of doing it.
With the setup above, I was able to run 2 natural-gas central-heat units, a large fridge, a couple of TVs with receiver boxes, computers and a few lights without the genny breaking a sweat.
Transfer Switch