Tica Bus is going to comparable in price to King Quality, about $100 round trip and the bulk of two days traveling. (You have to overnight in Managua.)
Tica Bus also goes in the other direction to Guatemala City and on to Tapachula, over the border in southern Mexico. Tapachula has a Comfort Inn and Holiday Inn Express, but it's hardly a tourist destination. You'd still have a ways to go before you could get to San Cristobal de las Casas, the big tourist draw in the Mexican state of Chiapas. You'd be in a non-CA-4 country at least.