Gudauri
It is a 2 hour drive away from Tbilisi, It has very nice view, Snow mountains and Ski resort. If you are a tourist, you need to book for a taxi to reach there. You will pay around 100 dollars for the whole day tour. You can ski and chill whole day in the place or book a hotel if you want to spend more days in Gudauri.
We spent 3 days more in Georgia after the wedding, So we have a lot of time to stroll the country, We walked in the Old Tbilisi with the view on the Narikala Fortress, We rode the aerial cable car to Mtatsminda Park to watch the capital from its highest point. We visited the New Tiflis and discovered the Wine Gallery that you could try, drink and buy wines in a very good price. There are more to visit in Tbilisi like the Flea Market Dry Bridge, Rezo Gabriadze Marionette Theater, National Botanical Garden of Georgia, The bridge of Peace and many more. You need to eat like a local too so we went to the Georgian restaurants like Barbarestan, Chamber Of Wines Mtskheta, etc. The famous food Kachapuri & Khinkali, wine, ambiance and staffs were fantastic and very good.
Tbilisi
Kazbegi
Kazbegi is 30 minutes away from gudauri so you can tour both places in one day. Kazbegi has a breathtaking view specially Gergeti Church. It is so amazing and worth to visit. You will pass military road, Jinvali Water Reservoir, Ananuri church and many more. If you are planning to visit Georgia soon, Don't miss visiting these places.