Guilin is 700 miles (1445 km) away from Xi'an, meaning that a swift two-hour plane journey or the comfortable bullet train are the most practical options. If you don't mind adding a detour and splitting the 15-20 hours of driving over a few days, you could break up the trip at Zhangjiajie National Park, famously the backdrop to the movie Avatar, and/or a trip up the world's longest cable car to the top of Tianmen Mountain. This 11-day itinerary also covers Xi'an and Guilin.
Duration: 2 hours
There are 5 flights per day from Xi'an Airport (XIY) to Guilin Airport (KWL). The route is served by Air China, China Southern, Beijing Capital, Changan Airlines, Hainan and Tianjin Airlines.
Duration: 11 hours
There is one bullet train per day from Xi'an to Guilin, leaving in the morning and arriving in the early evening. This departs from Xi'an Bei Railway Station, which is one of China's biggest rail stations, so give yourself plenty of time ahead of departure to find your way around and get through security checks and passport control.
The train arrives into Guilin Railway Station, the more central of the two train stations in the city. This is sometimes called "Guilin South" to distinguish it from Guilin North station. As always, book your train in advance to make sure you get a seat.
There is also one normal speed train each day, which leaves in the evening. This takes nearly 27 hours, though, so it's actually faster to wait for the next high-speed departure the following morning than to take the normal speed one.
Duration: 15-20 hours
If you prefer a road trip through the Hunan countryside, you will need to book a private transfer with a driver, as it's next to impossible to rent a car to drive yourself unless you're a Chinese national or have a Chinese bank account.
The journey by car will take you south on the G40 highway towards Neixiang, onto the S98 toll road until Xiangyang, and onto the G55. If you were taking the quickest route direct to Guilin, you would then stay on the G55 all the way to Yangzhou. To make a detour to Zhangjiajie, take the exit at Changde onto the G5513. This takes you to Zhangjiajie; when you're ready to move on, you can continue south, merging onto the G65 to Guilin. Note that there are several toll roads and partial toll roads on this route.