If you work at CUHK, Shatin is one of the good choices. In fact, the night view of Shatin is very beautiful especially facing the Shing Mun River. There are many people jogging, walking, cycliing, and fishing along the river at night. It can be quite relaxing after a long working day, and the air quality is not something you can find from Kowloon side.
For your concern on travelling to HK island, I think the faster way can be: KCR --> Tsim Sha Tsui East --> MTR. The whole trip takes about 40mins to Central.
Have you visited the Shatin Town Plaza which connect with the KCR? Shops there including Citysuper, Esprit, Mango, Pedder Red, Cour Carre, BodyShop, Manning, Watsons, U2, Bossini, UA Cinema..etc. Information from last year, the traffic of the Shatin Town Plaza was one of the busiest mall in the world. It was a small town but not that small afterall
