Yes, one night and one day is enough for the Rann. Visit Tropic of Cancer, Bhirandiyara, Ludiya, Magnetic Zone, Kalo Dungar and Dhoro Salt Flats for sunset. Stay the night and even return back for sunrise from the Salt Flats.
My personal suggestion...
Dont go to Rann during festive season. Instead visit in the first week of March when festival is over and weather is still good. Ride a bike or car with your friend(s) or solo, you will enjoy the road along only when there is no rush of tourists. Also the best photos come only when you visit off season(otherwise plenty of tourists are there to photo bomb your landscape). One day trip is enough for Rann.
Stay in a hotel in Bhuj (Regenta, Oasis etc) and do a day trip to Rann. If possible reach before sunset and moonrise, have some good panaromic photographs and then you will realise that that's it...that's all that was about Rann.
Please its not at all worth staying there in overhyped and overcostly tents. Instead go to Mandvi stay in Serena beach Resort. visit other nearby pĺaces(2 days are more than sufficient) Additionally you will end up saving alot from unnecessary hikes in fare.