You have plenty of space to get in there. Just put the front end up and get it from underneath.
Unplug the harness from up top, cut off the wire to make more room just above the sensor, heat it up and apply some penetrating oil, put either a 7/8 box end wrench or an o2 socket on there if you have one, and just slowly loosen it up. It's really that easy. Nothing needs to be dropped or removed to get to it.
That or just bring it to a shop. Should take them a half hour to do. An hour tops.