Uplistsikhe Transportation

I've been there two times.
1) first time I went there by train (elektrichka). In Tbilisi central train station there is platform, wich is separately from main platform. They call it Borjomi platform. The trains which go to Borjomi are taking their start from there. So, you have to buy ticket for this very train and went till station "Kva-Khvreli". from this station you need to walk a kilometre or maximum two to get to the place. The train ticket costs approx. 2 Laris.
2) second time I was there by minibus. Me and another Vt member (julie - travelmad478) we took minibus (marshutka) from Didube bus station (in Tbilisi) to Gori. (that costed 4 Laris). Form Gori we found taxi wich took us to Uplistsikhe for 20 Laris. He waited for us and took back in Gori.

I must say that both transports - the train and the bus are dirty and not much comfortable.
Also, the train is taking start at 7 AM and the last one back you have at 5 PM. So you will have some limit in time.
As for minibus you can take it from Tbilisi no matter when, but as for coming back there must be limit also.
Uplistsikhe is somewhere between Kaspi and Gori - somebody might suggest you to go there from Kaspi. But I was told that it is much closer from Gori and the roads are better.
Btw, it's in 15 kilometres from Gori.
one more note: if you go there by train there is the station called Uplistsikhe. One local told me long time ago that better to come down from train on station Kvakhvreli. Cuz it's nearer to the place then from the station Uplistsikhe.