I visited Un er-Rasas on a short trip from Madaba, with a rental car. The road is more or less signe-posted from either the King's Road or the Desert Highway (small road on the right shortly after the airport).
We arrived in the late afternoon. They is quite a big vistors' center, but only the tourist police station was open. The ticket office was closed, so we entered for free. We were the only persons on the site.
The site consists of a large ruined city in various stage of restoration. The interesting part is the churches mosaic floors. The St Stephen church floor is visited from a stairway, an is covered by a kind of hangar. The floors are spectacular representing animals, flowers as well as towns of the region.
We then moved to the church of Lions. It seemed rather tame, covered with sand, until we discovered that under the sand lies the mosaics. Part of them only are visible, but getting on your knee's to push the sand aside to reveal the mosaic gives the impression to be the first person to uncovered a treasure.
We then climbed walls to get to the churches of the River and of the Palm Tree with more mosaics to uncovered.
About 2 km north of the site, we finished visiting the stylites tower, which is now completely restored.