Mid-20's overnight should be no problem. I boondock in those kinds of temps all the time and our TT has no special cold weather features.
If you have water hookup, it might be a good idea to unhook and drain the hose. I wouldn't worry about the sewer hose -- it won't freeze enough to hurt anything.
If you were expecting below freezing temps for a couple of days, you would need to be more concerned about pipes freezing.
Wayne
Wayne & Michelle
1997 Safari Sahara 3540