My experience with the whole house moving lark has been pretty negative although it helps that we got on well with the sellers and did most of our discussions directly, then responding to the estate agent with "our" response awaiting the seller's agreement which of course we got.
The house we're buying has a clear picture in the brochure showing the rear garden and the closeness of the railway line, and that was a put off to some viewers although it shouldn't have been a surprise. Another "really wanted 3 bedrooms" (well why look at a 2 bedroom home in the first place) and many other really stupid things. Much of the time it seems people were persuaded to come and have a look by the agent so it looked like they were doing their job and earning their fee even though the property was clearly not what they were looking for. If people can't be bothered to read the leaflet, and can't imagine that a 15x12 room is more than big enough for a double bed, a couple of wardrobes and a table, then it may well be better for you because they're also likely the sort of people who are going to cause trouble throughout the selling process as well.
I scanned the floorplan, resized it in MS Publisher to 1:10, then created boxes 1:10 of furniture we had, and shuffled them round (a bit of an electronic version of graph paper planning) to see how things fitted and how things might work. We both sat down for a couple of evenings optimising things to know we could achieve what we wanted - except there's no space for a model room but enough space in the garden for a nice big shed) before putting in our offer, and we've subsequently done similar with the garden. We've chosen the paint colours we want, touched up photos with the colours, done mood boards and are ready to start decorating the moment we get the keys. But not everyone is as organised as we are.
In your situation, maybe when you get viewers have a double quilt down on the floor so you can show people what room there is when there's a bed in situ, and if you have any 'spare' furniture in one room dot it around the others. That'll probably help.
Just don't be tempted by any of these. http://www.telegraph.co.uk/news/picturegalleries/howaboutthat/11950433/Horrible-houses-Terrible-estate-agent-photographs.html