The happy trails are leading Roy Rogers to the recording studio. The king of the cowboys, now 78, is working on an album that will include Randy Travis, K.T. Oslin, Ricky Van Shelton, the Oak Ridge Boys and Restless Heart. "It was great meeting Roy Rogers, a true living legend," said Larry Stewart, the lead singer in Restless Heart, "and the whole band is thrilled beyond belief about recording a song with him." Roy's album is due in April 1991.