OP, ammeter measures "amperes". Daily energy use is measured in "amper-hours", and for this you need AH meter.
You can put clamp-on ammeter on when you're running your fan at slow, med and high speed, and it will read 1, 2, and 3A respectively. You can get these numbers from specs, not much need to measure, right? What you don't know is how many hours a day you run it on slow, med and high. The same with TV - you know it's current but don't know how many hours you or somebody else is going to use it, and there can be other devices running simultaneously with TV that you haven't mentioned yet - sat receiver, DVD, videogames etc etc.
It's hard to estimate daily energy use until you list all your devices with their currents and hours of run. With more than one person in trailer this estimate won't be too accurate. You need to actually measure energy use for a few days in varying weather, to get a better picture.
