It's easy to reach Wadi Rum by bus either from Petra or Aqaba.
Nights are cold, but blankets are provided.
What to do You have to pay a 1 JD entrance fee to Wadi Rum nowadays. It's possible to pay with credit card, although they will try to add some costs. Either you stick to the guesthouse which has the official monopoly on the tourist business which means high prices. Either you walk to the village where there are guides offering their services for cheaper prices. A full day by jeep including a night's sleep in a bedouintent will set you back 60 JD for the jeep.