You could be tired from seeing umpteen number of Churches in the Caucasus, but I highly advise you not to miss Jvari. This place provides you with the perfect combination of a stunning location, beautiful architecture and an area steeped in history.
At Mtskheta you will get accosted by a lot of taxi drivers who would take you there. With my foreign looks I got told prices from 20-40 Laris. Instead, I went to the tourist information center in Mtskheta and got told that it is possible to hike up the mountain to Jvari. They gave me a free map with a trail to follow. However, they did warn me that the trail is unmarked and people have got lost before.
I went for it anyway. The trail is unmarked and he climb is hard, but not impossible. From Mtskheta to Jvari, it took me around 90 minutes of hard work.
How not to get lost :- Since there are no marked trails, when you approach the foot of the mountain, you will see car/truck tracks going up - follow them. Eventually these tracks wear out, but there is then a combination of a well trodden path and cow dung from the local villages in the area. Follow it until you hit the main road at the top of the mountain which will get you to Jvari.
The climb was hard, but seeing Jvari was worth the pain and the biting cold!