Back in Oct 2011, following the local devastation of TS Irene, I started a thread about PTO Generators...that being said, I feel for this thread starter.
Like house or car insurance, when you have a house fire or car accident, that is not the time to be shopping for insurance. The same can be said for backup or standby power. The time to buy is when you are not being influenced by the sales guy saying "this is the last one" like my neighbor did just yesterday....ending up with something way smaller and much less than he both wanted or needed.
I have had two generators. First a gasoline powered unit that was 4000w and it did a decent job. However, as has been stated, it was another engine, and if not run all the time, may or may not start when wanted or needed. It also could only power certain items and the extension cord switch got to be a pain. My second is my current PTO genset. My tractor is run frequently and gets frequent service. I know it will both start and run.
As for many discussions about what to run...when the power is out, my house takes precedence over most other needs. While living in the Northeast where we are subject to snow as well, with my genset on the PTO, I counter balance with my front loader, which if needed, I can use to push a path to the road and then reconnect genset to the house when done...that short down time will not hurt anything in the house.
No matter which way you go, I strongly suggest bringing in a qualified electrician early in your planning. I did and knew up front what was going to be needed to get on line up front beyond the genset. I opted for the double throw connection vs the selected circuit route. I connect to the house and the house is powered. I choose not to run high consumption appliances such as my electric range, electric dryer and other heater type appliances during a power outage. But I do not have to worry about walking into a room and being able to flip the light switch...they are all connected.
Go in knowing what you have to power the generator and what your needs are and you will probably come out feeling good that you have done your homework and have covered all bases. With a tractor, yes, a small engine can run a larger generator, but at what cost. Larger units cost much more and also consume more energy to get up to power...and will choke a smaller engine if you try to draw more power than the tractor can generate.
So, for now, grin and bare it, but as soon as you can, start the process to find your power insurance for the next outage.