Just visited (March 2014), while in Burkina it's quite easy to see. The most convenient big town to start with is Gaoua (the capital of Sud-Ouest Region).

Small buses from Gaoua to Banfora via Loropeni depart from downtown (not from the main bus station), while in Loropeni (one hour drive on a dirt road) you will be dropped in the center of the town, where from there is around 4 km to the ruins (in the direction of Banfora), if you dont want to walk, you will probably find someone with the motorbike to give you a lift (should not cost more than 500 CFA).

Ruins are not visible from the main road but they are well marked (entrance fee 1500 CFA + 500 CFA for making photographs). Half an hour should be enough to see all the site (it is not big) but remember to take plenty of water with you as there are no shops / other ammenities on the spot.

If you go furter to Banfora there may be an evening bus (small) there, if not in the center of Loropeni there is very basic (no electricity, water in a bucket) hotel (auberge) to stay in.