Actually we've been to the grasslands and were quite impressed. Well worth a visit. As for how much time we've spent in NM: We've spent a week in Silver City and a 3 or 4 days in Carlsbad. The same in Grants, Taos, Roswell and Bloomfield. Spent more days than we wanted to in Moriarty waiting for a truck part.
We've been to White Sands, Carlsbad Caverns, Capulin, the lost Catwalk, Bottomless Lake and Gila Cliffs multiple times. Been to Bandara, El Malpais, Chaco Culture, Taos Pueblo, the radio telescopes in near Soccorro, Rockhounds, City of Rocks and Bandelier. Plus others that don't pop to mind.
But we are just visitors and will never know the state like you do as a long time resident. Just like visitors to Florida don't know the state as well as we do.