PROMOS

It’s not unusual for stars of new TV series to hit the trail to promote their upcoming shows. But stars of ABC’s fall Western, “The Young Riders,” have been doing that for real. The show is built around stories of young Pony Express riders, so this week, some of the stars were in the saddle for the first few miles to launch a cross-country ride by the National Pony Express Assn. Other cast members will join the riders as they pull into the California State Fair in Sacramento on Sunday, completing a trip that started last Sunday in St. Joseph, Mo.