"Bonanza, Volume 1." Republic. $39.95. "Heaven is gonna have to go some to beat the 1,000 square miles of the Ponderosa," Ben Cartwright observed on this series' first episode back in 1959. "Bonanza" was certainly heaven for NBC. The first Western to be televised in color, it ran more than 13 years and for several seasons was TV's top-rated program. That first broadcast and another from 1964 with Charles Bronson have now been packaged on cassette (two others comprise a second volume). Diehard fans may enjoy the memories, but others will find the offering thoroughly earthbound. The stories are simplistic, the staging stilted, the dialogue elementary. Information: (213) 306-4040.