Quoted:
3) Use the inverter off the Bronco battery,bad choice,very bad. After you notify the local building department and the electrical utility that you are planning to generate your own power (which is what you are doing). Then you will go through the permit process. You will need an automatic transfer switch that is rated for what the local utility deems necessary. Most likely you will need a licensed electrical contractor to install your system.
You might think I am joking about option #3, I am not, The local power company and thier lawyers will get very pissed off when you send 120 volts down line and kill one of thier linemen because you or your wife forgot to turn off the breaker or switch.
Buy the UPS
Urban legend. If you try to back feed power through the line, you will be trying to power everything else on that line including every load still connected in your house. All you will do is pop your overcurrent device or fry your power source.
You need one of these emergency cable releases:
http://www.naturalhandyman.com/iip/infgar/infgar61i.html
They have them at Lowes or Home Depot.
If you are really set on doing this electrically, before you burn your garage down, isolate the power to your garage by installing a disconnect on the outside. You can then backfeed to your hearts content. Or you can go turn the breaker off to the garage yourself, eliminating your wife from the equation, and do the same.