I have a 2009 corolla w/automatic transmission. Can it be modified to tow 4 wheels down?
No, see this link, http://toyota.custhelp.com/app/answers/detail/a_id/7710/~/is-it- possible-to-tow-my-toyota-with-all-four-wheels-on-the-ground%3F
Yes use a car dolly on the drive wheels or buy a pair of "free wheeling towing hubs". They bolt-up to the drive wheel brake hubs & are a bearing to not permit the drive members to turn. The drawback is you have to put the on & take them off to tow or drive.
A dolly would be a fine idea.