Tocharian on Emperor:
1st UHV (5x Open Borders): fine, you can get in before 0AD
2nd UNV (incense, silk) : fine, I managed it in 0AD
3rd UHV (spread Buddhism to 5 Chinese cities):really difficult, managed it on the last turn and I had to pull several stunts
While having my Golden Age from the achievement of 2 goals in 0 AD I moved into Central Asia (having settled the Ferghana valley before). Only Samarquand (and Bactria) had Buddhism (it never spread to the Tarim valley). So it became key to capture and hold Samarqand. Please note than this section of the map gets invaded by Horse Archers like every few turns at that period of time.
Due to the whipping of walls and a combination of Bowmen and Spearmen I was able to fend off the Barbarians and in between the invasions to rebuild the plundered resources with the help of the scores of slaves coming from these attacks. I had teched to Selective Breeding which allowed me to extensively exchange technologies round about the same time and therefore transformed me from a backward nation of sheep herders into a medium advanced kingdom. Moreover I got access to Camel Riders which further helped with those horse-riding Barbarians. (Still, fending off Strength 7 Horse Archers and Strength 8 Heavy Horse Archers is no easy task)
Then the spawn of the Kushans happened. So I reloaded, moved all my army out of all cities in Sogdiana, Bactria and Ferghana (god bless you did not code some more Barbarians invasion in that year) . Then I let the Kushans spawn .. and moved my army in again. After the Kushans had lost all their cities but one in only 1 year they were ready to become my vassal.
Naturally I had lost many buildings in the process, several trade treaties had to be renegotiated as I had lost access to my resources for a time and I also had lots of unhappiness because many of my citizen considered themselves now to be Kushans rather than Tocharians. Still, you can handle such things.
The next challenge was to reach the ability to build Buddhist missionaries. The only possible tech to be reached in time was State Religion. I got this by around 100 AD. However I could not switch easy any more, as my stability was too compromised, so I decided to gain a second Great person in order to have a third Golden Age (the first one I also had in the the years after 0 AD in order to prolong the Golden Age from the achievement of 2 UHV goals, didn't think I needed another one in those days)
By 136 AD I got my 2nd Great person and started another Golden Age. I therefore could switch to State Religion without losing Samarquand. Still, I had forgotten that one could only convert to a state religion which is present in half of your cities. So I pulled off my last stunt. I gifted all cities but 4 to the Nan Yue after moving out my army. Then I switched to Buddhism. In the next turn the Nan Yue collapsed due to overextension. Then I moved in again. About the lost buildings and trade contracts I didn't even care no more.
Somewhat on the way I had picked up Metallurgy and Samarquand had a Blacksmith and other productivity enhancing buildings. So I was able to produce a missionary every 3-4 turns and send them on the long way to China.
God Bless I already had a road from Samarquand till Dunhuang, which I extended then into China.
Literally on the last turn the last missionary reached his goal. However I really needed many stunts to pull this off.
Pros:
1) Fighting Barbarians successfully can be fun and creates excitement
2) Moving from the inhospitable Tarim desert into the comparably fertile valley of Ferghana and then on to the plains next to the Amu Darya feels ... damn good!
3) In the end I had 6 cities in the Tarim Basin, 2 cities in the Ferghana valley, 2 cities in Bactria and 3 cities in along the Amu Darya and the Syr Darya and still expanding. That is not bad for some backward desert twelling sheep herders.
Cons:
1) Buddhism not spreading into the Tarim Basin (despite availability of 6 cities) is not fun.
2) Bhodya (Buddhist Holy city) not reachable during the whole game. At first it is occupied by Mauryans which collapse too fast to the Sunga in order to build good relations. The Sunga are extremely hostile and only warm up when they get stomped by the Saka, soon after the Sunga collapse then as well. Eventually the hostile Saka hold the city until 200 AD and there is also no dealing with them short of invading North India .. which becomes even less an option when the Saka capitulate to the Parthians and become their vassals.
3) Kara-Khoja. This city (in the Tarim Basin) seems to give access to silver. Actually the program even advices this settlement spot by giving it a blue circle. Silver is always welcome and not the least to make the bigger cities in Central Asia happy (especially with all this "We feel we are Kushan"-nonsense). However, first surprise, your settler can reach a spot on the desert that your workers actually cannot reach. Hence, in order to move workers to the Silver you must go all the way around. However when you finally reach the spot after many turns then it laughs you into your face by saying ... no, no, there is a forest on the mine and you need Blast Furnace to mine me ...
I suggest to remove the forest and to let workers enter this spot.