Are you normally turning off the tank each time you are finished with it?? Don't forget that turning off the tank DOES NOT remove the gas in the lines unless you turn the tank off FIRST.
To empty the lines leave the stove burning, turn the tank off, then when the stove goes out by itself, don't forget to shut the stove off!!).
Most people don't do that but simply leave the tank on all the time and use it as you would in a sticks and bricks. If you are on the road and encounter an area where the signage indicates the gas should be turned off (tunnels, gas stations, for example), it should then be turned off at the tank. (Also make sure the fridge is off and not simply on "auto" for gas stations so it will not be continuously trying to light.)
A little smell of gas around the tank area is not unusual especially on a trailer as the regulator might vent a bit into the open air. There is sometimes an escape of gas when a trailer tank pigtail is removed too. As long as it is not there ALL the time, there should be no problem.