Sleep Configurations

East to West beds are more difficult to make up.
If sleeping 2 people in it, one person has to climb over the other in order to get out of the bed.

North to South beds are usually island beds that offer walk around bed making as well as under the bed storage. Its also easier to reach overhead cabinets and side closets and night stands are normally used for more storage.

As you can see North to south island beds are convenient to use plus more storage.

Also consider a comfortable place to sit. Some dinettes are horrible once you sit in them for an hour and a sofa would be a very welcome addition to a floorplan like that. If you choose a floorplan with a dinette only (no sofa) then make sure its a comfy dinette-long-term for the inclement days/nights.
Make sure you spend enough time in it when you're shopping for a trailer.
Make sure you have enough cabinet space to fit everything you plan to haul with you.