Although both are located in the Nantou vicinity, the distance between those 2 places are quite far apart.
1. Taxi / Cab
The most convenient option would, of course, be by taxi or cab.
Downside is that this option would be expensive unless if you have a group of people traveling together to share the expenses.
Taxis can be found near the Shuishe Pier of Sun Moon Lake. Alternatively, if you spent a night in one of the minshus around this area, you could ask the owner or minshu operator to call a cab.