We have the Odyssey Export. We have the overnight awing and we find that there is very little no room to fit anything else on top of the mattress once the sheet and quilt are pushed into the centre. (We store our four pillows under the bed floor.) In fact at the moment we do not have the awning fitted and it is making folding up so much easier, but we will fit it again soon, as we head into the Karijini National Park. The weather forecast is for some rain next week, bugger! It is like other camper trailers, if only they allowed just a little extra room. But then there would be extra weight and cost I suppose.
But seeing as you do not have the awning why not give it a go and see what happens. The awning does take up a bit of room. Remembering to keep it all in the centre. Kevin and Kris