An Australian man on a globe-trotting mission, averaging about 31 miles per day, said in New Jersey he is nearing his halfway mark. Tom Denniss, who has made it his goal to travel the world, running until he reaches 18,000 miles upon his return to his hometown of Sydney, said yesterday in Princeton he is about halfway done, and will visit New York, Connecticut, Rhode Island and Massachusetts before taking a plane to South America to continue his 700 consecutive days of running. Denniss, whose wife is accompanying him on his journey and acting as his support crew by following him in her car, said his run is raising money for the international charity Oxfam, which aims to help communities become sustainable.