The first day I would build
Start with the Liangzhou core before adding the grotto outing.
- Use Leitai Han Tomb as the first city anchor.
- Pair Wuwei Confucian Temple or Kumarajiva Temple with the same city-side route.
- Save Tiantishan Grottoes for a separate clear-weather block.
Wuwei is strongest when the first day explains why the city matters. Leitai Han Tomb gives the route a real historical center, especially because of the Flying Horse association that is now tied so strongly to Gansu.
After that, keep the city route modest: temple, food, a short walk, and an easy return. The grottoes deserve more attention than a rushed extra.