I visited the Thracian Tomb of kazanlak in January and then of Sveshtari in May.
Staying overnight in Isperih, I took a bus from the main bus station of Isperih to the village of Sveshtari and from there walked about 2 km to the site. The bus leaves about once every two hours.
Right after me a few dozens of German cyclists arrived followed by their large bus, which meant that one German-speaking guide gave them a tour of the site and one English-speaking guide gave me a personal tour.
She took me to the 3 tombs on the site (but there are many more out of the site), so unlike the only one tomb at the Kazanlak site, this site resembles more or less like the WHS at Vergina in Greece.
The main tomb / room is structurally supported by caryatids, which is unusual in Thracia as well as in the USA, so I thought it would be nice to have such a tomb.
Unfortunately, no photos were allowed inside of the tombs.