Make sure you label what it is properly. My friend was looking at 5th Wheel Toy Haulers and he came across one that was simply labeled as a 5th wheel. He's losing out on a lot of potential buyers with this simple mistake because if you need a toy hauler, you wouldn't consider anything but a toy hauler, BUT toy haulers come in many varieties (i.e. Travel Trailer, 5th wheel, Class C and Class A). He may be pricing it wrong too.
I'd fill out as many details as you have. Give clear pictures that show as much as possible. I've seen people post pics for RVs and houses and what not and it's just a corner of a room.
I'd also tell people how much you love it, but your needs called for something larger, so they know that you love your trailer and there are no issues, it just didn't fit your needs anymore.
In this case, less is never more. More is more. Kill them with info. Besides...the more info you have, the more likely the listing is to show up in searches due to more keywords.