Getting there
Nine hours from Tbilisi, six from Kutaisi. The last three hours are tight mountain switchbacks — a 4x4 or high-clearance minivan is not optional in winter. Flying into Mestia from Natakhtari is the shortcut but weather-dependent.
Mestia — first day
The town is compact. Svaneti Museum (icons and manuscripts), one Svan tower visit, and an evening at a local supra for hospitality you won't find in Tbilisi.
Day trip to Ushguli
Two hours each way from Mestia on rough road. Ushguli is the highest continuously inhabited settlement in Europe — cluster of Svan towers under Shkhara. Go, stay for lunch, come back.
What to skip
Don't try to do Mestia as a 2-day trip from Tbilisi — the drive eats both days. Three nights minimum, four if you want the Koruldi Lakes hike.