Complex sentence: For the next few decades, the group released albums and toured and had a country hit with "White Line Fever" (1980, a cover by Merle Haggard) and then became the Burrito Brothers.
Split into simpler sentences: For the next few decades, the group released albums and toured. It had a country hit with "White Line Fever" (1980, a cover by Merle Haggard) and at that time became the Burrito Brothers.