You can take overnight train it leaves Baku at 08:45 and arrives into Tbilisi the following morning at 11:40.
Baku’s central railway station is accessible by metro. For exact fare pls call to railway station
What time of year are you looking at for this trip? The shortest driving route from Tbilisi to Baku is the one going through Ganja but in my opinion is not worth it as there is not much to see. Also expect it to take much longer than 6 hours as you may potentially be stuck at the borders for quite a while.
If you have more time, and would like to drive, I would highly recommend taking the other more Eastern route which is much more scenic and offers numerous interesting stops at cities and villages such as Zaqatala, Qakh, Sheki, Gebele, Shamakhi. You can turn this into a few days trip spending a night or two at one of the mentioned cities. Again this will highly depend on what time of year you are looking at as weather conditions may make it an unpleasant drive.
Thank you for such detailed info. Im considering first week of March, so still not sure about weather conditions in mountains
You take a bus but this will take around 10-12 hours. But this is a cheap option - around 15 euro.
Planning to be in Baku 1st week of April 2018.
Is this a good time of the year to take the more scenic drive that you suggest?
Do you think it would be easy to find a driver (ie via the hotel) to take us eventually to Tblisi with a few stops along the way?