There is some useful information in the two threads shown below. One is for a first time caravanner going from motorhome to caravan. The second one has some useful information. But there aren't any caravans that stick out as a big NoNo, but you don't say whether you are interested in older van, relatively new, or brand new, or what size and layout or what tow car. So you need to be bit more specific.
"Changing from a motorhome to caravan. Advice please" by Skeggysue.
""Which caravan are worse for damp" by smd