Today I walked a lot. At first made a ride on metro to Avlabari, then with taxi up to Sameba. Then down to old city. Then up to Narikala and then near Mother Georgia monument to Rustaveli Boulevard.
From there with bus nr 124 up to Mtatsminda amusement park. with funfunicular down to the Pantheon and again by foot again down to the Rustaveli Boulevard.
I guess some 8km at least.