I have noticed the hotter the weather gets the more power is used. On a cold day under 70 deg F - I could get by with 500 watts or 1/2 of a KW per day. When its hotter 90+ F deg then you could figure about 1000+ watts, most of this is used by the refrigerator and the fans to keep the trailer cool. The problem is when the solar panels get supper hot - they produce 20-30% less power, so keep that in mind when you are sizing your system.
Another problem that I have noticed is that the solar panels really need to be washed every few week to a month at the most, for some reason they get very dirty.