Hi jmartin,
In general if the freezer is close to zero degrees F, the cooling system is working. If the refrigerator is warmer than 40F, it could be:
1) air leaks in the refrigerator cabinet - perhaps the door(s) aren't closing completely.
2) if temps and humidity are very high, the frig may be struggling and could take overnight to cool down.
3) if the frig is packed such that air circulation is reduced significantly, the cold air will not circulate to all areas
4) if you open the door(s) and leave them open for a while as you think about what to take out, you'll find that RV refrigerators can take a very long time to recover.