Why autumn works in the Georgian mountains
Georgia's high country turns in the last week of September and holds colour through roughly the third week of October. Kazbegi, along the Georgian Military Highway about three hours' drive north of Tbilisi, is the reliable bet: beech and birch on the slopes below Mount Kazbek, and the Gergeti Trinity Church walk from Stepantsminda village, a climb of around two hours up a steep track. Days sit near 12-15C in early October and fall toward 5C by month's end, so bring a windproof layer and sturdy shoes rather than trainers.
Booking matters more than route choice. Guesthouses in Stepantsminda fill quickly on October weekends, and rooms with mountain views cost more than village-facing ones, though I would still pay for the view here. If your dates are fixed and the forecast turns wet, Svaneti around Mestia is a decent alternative but the drive from Tbilisi is long, close to eight hours, so most travellers pair it with a flight to Kutaisi instead. Skip the cable car at Gudauri in autumn; it runs mainly for winter skiers and much of the walking there is exposed.
Tbilisi on foot when the heat has gone
Tbilisi is at its best from mid-September, when the summer heat breaks and the old town becomes walkable all day. A good loop starts at Freedom Square, climbs through the narrow lanes of Sololaki to the Narikala fortress walls, drops into the sulphur bath district of Abanotubani, and finishes along the Mtkvari at Rike Park. Allow three hours with stops. The cable car from Rike Park to Narikala is cheap and saves the climb; the funicular up Mount Mtatsminda is worth it near sunset for the city view.
For food, the Vera and Vake neighbourhoods have the strongest everyday restaurants, while the old town trades on location and charges accordingly. Look for khinkali priced per piece and grilled meats by weight, both standard across the city. A reasonable dinner with wine in Vera costs noticeably less than the same meal a few streets from Sioni Cathedral. I would book a hotel in Sololaki or Vera rather than the old town itself: quieter nights, better value, and ten to fifteen minutes' walk to the main sights.
Kutaisi and the west as a second base
Kutaisi has become the low-cost entry point for western Georgia, with direct flights from several European cities and a compact centre. From here the Martvili canyon and Prometheus cave are each under an hour's drive, and the Bagrati Cathedral and Gelati monastery sit within the city or a short taxi ride out. Autumn rain is heavier in the west than in Kakheti, so build in a flexible day. Roads to Mestia and Ushguli can close after early snow, usually from late October.
For wine country, Telavi and the Alazani valley in Kakheti are the better autumn base, with the Rtveli grape harvest generally running from late September into mid-October. Sighnaghi is prettier but busier and pricier; Telavi feels more like a working town and puts you closer to the wineries around Tsinandali and Napareuli. Two nights in Kakheti is enough for most visitors, and I would take Telavi over Sighnaghi if you want to eat well without paying a premium for a view.
What to book and what to leave out
A sensible first trip runs five to seven nights: three in Tbilisi, two in Kazbegi, and a night or two in Kakheti, all connected by the Georgian Military Highway and the Kakheti road, both of which are straightforward in a hired car or with a driver. Book mountain accommodation first, since supply there is thin, then build the city nights around it. Mid-October is my pick: colour is still holding in the foothills, the harvest is on, and the Tbilisi guesthouse rates have not yet climbed toward the winter holidays.
Leave out the Black Sea resort of Batumi in autumn. Most seafront hotels scale back services after September, the beaches empty, and the drive from Tbilisi takes five to six hours. Save it for summer. Also skip guided day tours that promise three or four regions in one day; Georgian roads and mountain weather make that an exercise in sitting in a minibus. Pick two bases, walk them properly, and eat where the menu is in Georgian only, which usually means the kitchen is cooking for locals rather than for the tour trade.