This is a splendid route that takes you from the capital (constitutional) of Bolivia through breathtaking highlands all the way to the gorgeous wine country of Tarija.
But before you leave Sucre going south, take a side trip east to what I think is Bolivia's best traditional market town, Tarabuco. On your way there, make sure to stop and walk with the dinosaurs at Cal Orcko, which contains over 5,000 tracks of 294 species of ancient beasts.
Going southward, your major "pitstop" worth spending at least a day in is Potosi, a town of intricately colored doorways and some of the best museums in South America thanks to its affluent history from mining. Climb the little hill of Tarapaya and find a natural thermal hot spring on the top waiting to give you a dip with a great view. Potosi is also a major crossroads for transporation going west to Uyuni.
Before you get to Tupiza, you might be tempted to just get off and do some hiking around the picturesque Laguna Kharachi Orcko, but if not wait to get into town where you'll find lots of outfitters to take you horseback riding or mountain biking through the area canyons and valleys.
By this time you will be thoroughly convinced you are in as much the wild west as west Texas, and so it shouldn't surprise you that your destination Tarija is the rodeo home of Bolivia, and also the wine capital, and also the flower capital. To relax at the end of your trip, take a row boat out on Lake San Jacinto.