During high season there is at least one bus that goes straight from Nanning to Detian. 8:30AM from Langdong bus terminal on Minzu Dadao, ¥50.
During low season there are buses going from Nanning to Daxin on a semi-regular basis. In Daxin there is a single bus from the bus station that goes to Detian at around 11:20AM, though again, only during high season. During low season inquire at your hotel how to get to the waterfall. If you can manage to tell them that there is no bus from the bus station they will direct you to where 12-person vans regularly depart for Xialei (¥12). If you tell them that you are going to Detian they will drop you off in Shuolong. From here you can easily find a smaller 6-person van that will take you the rest of the day (¥3 though they may try to convince you to pay more if they are having trouble finding additional passengers).
Detian Scenic Zone. At 200 meters wide with a 75 meter drop, the Detian waterfall, located primarily on the Chinese side of the Sino-Vietnamese border, is definitely the highlight of the Detian Scenic Zone, as well as being the second largest waterfall along a national border. Because the amount of water cascading down the waterfall differs with each season, the waterfall will change appearance from a raging torrent to a peaceful splash, the upside being that the waterfall is worth visiting year-round.¥80. edit
Detian Waterfall. Scenic spots are littered around the road besides the waterfall permitting several different angles from which to capture the falls. The scenic route takes one up right besides the waterfall to each of its several different levels. At its base there are several rafts that during high season will take one a few meters out for a close-up shot of the waterfall, though for a rather steep ¥20 fee. Climbing the path besides the Falls is supposed to be especially relaxing do to the high concentration of negative ions in the air. A tiny Buddhist shrine at the top of the Falls completes the image of tranquility.edit
Cannon Mountain, (on route to the 53 Boundary Marker). A steep ascent to Cannon Mountain. The path leads up to a vantage point on which the Chinese deployed several cannons to oversea the Vietnamese border. A sign at the base warns travelers with heart conditions or acrophobia not to attempt the one and a half hour climb, a warning that should be taken quite seriously. The path upwards is overgrown in many parts with local vegetation including thorn bushes. The stairs themselves are uneven and in many places no wider than the rung of a ladder. Numerous excellent vantage points for photographs can be taken after only 30 minutes of climbing. You have been warned.edit
53 Boundary Marker. Those hoping to visit the boundary between Vietnam and China and take a quick photo of themselves tiptoeing into Vietnam may be disappointed to notice a security guard whizzing by them on a local three-wheeler as they near the marker. Photographs are allowed (though the guard himself doesn't seem to enjoy being photographed) but crossing is strictly prohibited. For those determined to get their "Straddling the national boundary" photograph consider taking your pictures of the stone marker, then beginning the ascent to Cannon Mountain and returning after about 30 minutes to see if the guard is still there. Obviously actually crossing the border with the intent of entering Vietnam should be avoided, as attested to by the large warning sign listing the various monetary penalties for disrespecting proper immigration channels. The stone itself is written in Chinese and French and stands a few feet high.edit
Most of the souvenirs on sale will be available in any Chinese tourist spot. The exception may be the selection of perfumes, (although several tour guides advice to do not buy take perfumes as they could have undesired effects on the skin. The price of the perfumes can be bargained until ¥20 for two perfumes).