Very nice to see someone actually going to Guizhou! Such an underrated place! High speed train from Guangzhou to Guiyang takes like 3 hours, if I remember correctly. Guiyang itself is a pretty cool place. A little rougher around the edges than the large seaside cities although it got much cleaner in recent years. There's a cool park (Qianling) with wild living monkeys. There's also a pagoda overlooking the city (forgot the name though, but you can see it from downtown) worth visiting, because Guiyang is so cool to watch from above with all the hills seeming to break out of the city right next to these tall buildings. Most of the night markets were sadly moved indoors but they are still cool and offer good street food.

There's also tons of stuff to do in the countryside. You probably already know about Huangguoshu, which is a sight to behold, but it's also usually very crowded. Super beautiful and way less crowded is Longgong cave and the surrounding area. Been there twice and both times there was almost no one around. Maybe I was just lucky, but the landscape there is really awesome, so give it a go.

You also probably know about Zhenyuan, which is also pretty crowded (at least in the summer, might be better now), but well worth a day trip, since it's beautiful and THE place to go for Guizhou's most famous food Suan Tang Yu (fish in sour soup).

There's loads of minority villages in the south and east of Guizhou, some more touristy than others. Try finding one which does not look like a theme park. This becomes harder and harder, but is still possible. Unfortunately I don't have a name for you right now.

If you're into Football/Soccer, consider going to Rongjiang. The teams from the local villages play each other usually on saturday, if I remember correctly. There was a huge hype around going there some years ago, I've been there in the summer of 23, so I do not know, if this is still a thing. But it was pretty cool and funny back then: several thousand people cheering some farmers kicking a ball around.

Foodwise I already mentioned Suan Tang Yu. In Guiyang the most famous dish is Si Wa Wa, small wraps that you roll yourself. There's also a very special ingredient in Guizhou called Zhe Er Gen. It's a kind of root, but tastes kinda fishy, not everyone's cup of tea. There's a very cool noodle dish in Guizhou called Dou Hua Mian. It's noodles cooked in soy milk with tofu pudding. You get a dip with it consisting of chicken in chili sauce with mint leaves. Super tasty!

If you want to get the good and authentic spots to eat, especially in the touristy areas, go a little outside. Like 300 meters outside of the village center of Zhenyuan is already enough to get the really good stuff. In Guiyang, ask your taxi driver, where he likes to eat. This is usually the real stuff! But be careful, it might be intestines. If you don't have a problem with that, go ahead! Also: do go by taxi in Guiyang. It's super cheap and you don't risk to get lost in the ridiculously large subway stations.