If pushing a lawn mower seems like torture, take Kurt Larson's example and modify that mower.
Kurt Larson absolutely does not enjoy mowing his lawn. He'd much rather be working on electronics in his shop. To take a step away from having to put in the sweat and effort of mowing, he has modified his mower to be radio controlled.
He took his trusty mower into the operating room and started removing bits and pieces. The front wheels were replaced by 12V wheelchair motors attached to mini-bike tires. The rear wheels were replaced by free spinning casters. This setup should have plenty of torque and allow for on-the-spot turns.
His control system is a standard R/C setup using an off-the-shelf Futaba transmitter and receiver. However, his power system is where things get interesting.
You would typically see a massive battery pack for something like this. However, he realized that the quantity of batteries necessary to mow the entire lawn would be quite prohibitive in terms of weight. Instead, he opted to just do what we do in cars. He picked up a cheap alternator and mounted it to the mower's driveshaft. This alternator keeps the onboard motorcycle battery topped off for the duration of the mow.
As you can see in the video, this thing is quick. Not only does it move along at a brisk pace, but it snaps out turns pretty well. You can also see that Larson isn't quite free from the hassle of having to mow the lawn. His mower isn't autonomous yet.