Drive to Oni

On our trip to Georgia in early May, we plan to drive from Tbilisi via Kutaisi and Zugdidi to Mestia - probably spread over 2 days.
On the way we would like to make a detour to Oni, maybe even staying overnight.
Any suggestions on which road(s) to take ? Back and forth from Kutaisi ? Other convenient options ?
Help much appreciated.

Mestia-Ushguli-Lentekhi-Tsageri-Oni is possible - I have done it in summer 2011, but the road is far from being convenient - some scary moments on Ushguli- Lentekhi segment.

Google Maps gives the Gori - Tskhinvali - Oni option.

Is it possible/advisable to drive up to Oni this way ?

Tskhinvali is out of question - see South Ossetia.