Tiger Leaping Gorge is a must see for any nature lover. Very impressive.

okay, if my friend is coming to Yunnan, I will organize the trip as follow.

Day 1 in Kunming City,first stop,Kunming Museum of Urban Design and Development. It locates at 122 Tuodong rd. just cross the Municipal Musuem(still under maintaining work). The reason I think this would be a good start is you can easliy have a glimpse of Kunming's history,the present and the future plan of course. The model of Kunming city map, old photos of Kunming and,most importantly,you might be the only ppl there, no crowds at all, what a plus! No fee btw.
After that, Yunnan Nationalities Village (ticket 90rmb),locates on northeastern shore of Dianchi Lake, you can take A1 bus after you finish the museum. I think it might interesting for you guys, as there are 25 ethnic groups in Yunnan, and you can visit all of those 25 mini-villages there. The houses they live in, the clothes they wear,and singings and dancings can be amazed if you have never been there.There is a 50-mins performance during the day at the hall, 2p.m I think, you can go and enjoy,quite interesting. The village is huge, but if you still have time after this, you might want to take the cable car to Xishan,during which you can have a better view of Dianchi.

Day 2 in Kunming City, Kunming Kuchuang, locates on 101 Xiba Rd. Have you heard about Beijing 798? People say Kuchuang is the originical idea, and so we have Beijing 798. So you can find plent of bars, coffee shops and gallery there.
Then you can go to the Green Lake, of course! Just stop for a while to listen to the locals' singings and dancings~~Keep walking to Wenlin street (foreigners' street),and maybe walk around in one of the uiversities there too,might be different and new to your friend.

In the evening,you can go to Yunnan Railway Museum/North Railway Station on Beijing Rd, buy a tickey(not expensive) and get on a facinating train ride, it starts at 8p.m, and takes 1 hour ? So it is The Yunnan-Vietnam Railway, think about it,the old Meter gauge railway, the old carriages, would be great!

Day 3 in Kunming, you mentioned Stone Forest,well, I've been there, it is a magic work of nature,the vivid rock goups, but it would be very hot at this time of the year. I personally like Jiu Xiang better, it is a Karst landform,you can row the boat,see the water falls,and walk along the pleasant tracks,nice and cool. You can take bus from East Station of Bus Transportation Hub (not East Station) to Yiliang, and take another bus from Yiliang to Jiuxiang. There are many buses to and from Kunming daily, the ticket is 120 rmb, including the cable car.

Then it takes 1 week at least to go to Lijiang. 2 days in old town,just walk around and look at the old buildings and bridges, try the local food,see how they make the scarf and bracelets, and talk to the locals, ineresting! And tiger leaping gorge, I recommend the middle-gorge,and if you want, try the sky ladder there! Staying at Tina's for one night, and get back to Lijiang the next day, or keep going north to Shangri-La,which is more Tibetan like. Worth going. You can take train to Lijiang, as you might meet some interesting ppl on the way!

It is 9 days already,Yuanyang Terrace could be a very good choice then. I have never been there, but it is on the list. I think the newly planted rice in the terrance will definately look impressive,especially when you stand on the very top of the field.

Anyway, have a wonderful trip! :D