Welcome to the forum. Congratulations on having learned sketch up. Having the ability to build true to scale 3d models of your ideas is a huge help in designing something like this.
One thing you really want to be sure of is the position of your side doors relative to where your keister lands on your mattress when you sit down in the doorway. You want to be able to "sit and spin" (roll back and lift your knees, then pivot into your sleeping position with your head on the pillow). The less shuffling around you have to do to get comfortable, the better. To me it looks like your doors might be a bit too far forward, and you have plenty of room with your tires to move them back a bit, if so. You can check this by sitting down on your regular bed as if you were getting ready to lay down, then measure from your middle to the top of your pillow. That should be where the middle of your door is relative to the front wall. I'm large and don't bend as well as I used to, so I built my doors nice and wide so that I don't kick the door jamb quite so hard every time I swing in.
Also, you want to watch out for the height of your door sills. Many people complain that they left their door sills too high and the seal flange or threshold digs into the backs of their legs when sitting in the doorway. The rule of thumb is that the sill should not be anymore than half the thickness of the mattress, but I would keep it as low as practical. Mine is a 2x plus the lip of the seal flange, or about 2-1/4 inch with the edge trim seal in place on the flange. Yours looks like it might be a bit high.
One last thing, if you prefer the angular look, great (I was drawn to the weekender design to start); but if your design is boxy because you are uncertain about trying to build a curved profile, don't be. They're really not that hard and the curves provide inherent strength. If you can build a TD at all, you can have curves if you want them. If you don't, disregard this comment in its entirety.