There is no direct public transport to the area. You can reach the Sapareva Banya village by bus and then you should take taxi to the Panichiste resort.
If you start from Sofia, you should go to the Central Bus Station. From there, you can catch the bus to Dupnitsa town (written Дупница in Cyrillic) and then you should change the bus to the Sapareva Banya village (written Сапарева баня).