Mars One, a Mars colonization plan intended to be funded by a TV show, plans an unpressurized manned rover capable of traveling 80 km (50 miles). They said a possible supplier was Astrobotic Technology.
The Manned Mars Exploration Rover won a design award in 2010. Some features included live-aboard capability, a winch, airlock, and six foam core wheels. It featured modular construction so it could be assembled from smaller parts, and the suggested power source was radioisotope batteries. An example of RTG use is the Cassini-Huygens spacecraft whose radioisotope power system produces several hundred watts of electrical power.
It produces this amount power continuously with a slow decline over decades, and with even larger amount of heat production at the same time. The electricity is produced from the heat given off by radioactive decay.