The first day I would build
Keep the old city and the grassland idea separate.
- Start with Dazhao Temple, Xilitu Zhao, and Saishang Old Street.
- Use Inner Mongolia Museum when you want a broader regional context.
- Save Xilamuren or grassland routes for a separate day with clear weather.
Hohhot has enough city texture for a real first day. Dazhao Temple, Xilitu Zhao, and Saishang Old Street can sit together naturally, with food and shopping close enough that the day does not fight itself.
The grassland outing is a different rhythm. It needs time, weather, transport, and expectations that are not the same as an old-city walk.