I started off with a trailer system and I used it for a few winters.
If I were to do the same thing again (I now have a van mount) I would go for a trailer that had a lid/cover on or van trailer so I could keep the hoses from freezing. I would also not consider anything under 750kg, it must be braked and a minimum of 13" wheel size and single axle.
We live in a hilly area, and if you have to uncouple the trailer, there is no way you could hold it from heading off down the road. I used to carry around 2 bricks incase this happened, but I wouldn't do it now. We have 6 cul de sacs on our round that we couldn't turn a trailer around using the tow vehicle and they were all on steep hills.
As has been alluded to a small tank on the back will be an inconvenience, so you would have to make up for it by carrying extra containers of water - I did that - it was too much of a pain decanting water into the trailer tanks when needed. Better to get a bigger tank to begin with.