I've toured in Mexico, Costa Rica, Chile, Argentina, plus several daytrips in Ecuador. Also a bit of touring in Spain. Mexico is great if you pick the right region & season (northern hemisphere winter is best). I especially liked Michoacan state. If you want easy riding, the Yucatan is very good in the winter, assuming it didn't get trashed too badly by Hurricane Emily this week. I'm thinking of returning myself to Mexico this winter to bike in the highlands of Oaxaca and Chiapas.
South-central Chile ("la region de los lagos") and adjacent Argentina have some of the finest scenery I've seen anywhere on the planet, though it's not nearly as interesting culturally or gastronomically as Mexico. There are relatively few paved roads, however, and not even that many unpaved ones in the region. The Carretera Austral in southern Chile gets raves, though I wasn't there myself. It's much wetter, and some camping will be required. No camping gear was required on my 2 bike trips to Mexico (inexpensive hotels) or south-central Chile (hospedajes, e.g. bed & breakfast)
I think that touring in the mountains of Ecuador could be good. I did daytrips near Otavalo (north of Quito), Cotopaxi volcano (south of Quito), and Banos (east slope of the Andes partially down to the Amazon basin), and all were enjoyable. I've heard there's a pretty region between Cuenca and the Peruvian border. I was in Ecuador before the most recent economic collapse and dollarization, and don't know to what extent security has deteriorated.
Costa Rica is a lovely country that's well worth a visit, but I found biking there less satisfying than the other countries I've mentioned.