How to go about building this desk

Hi everyone, I'm 15 and want to build this desk I designed. The door on the right of the "my room" pic is my closet, no need for accessibility. To the left of the desk is my actual door hence the desk not reaching all the way and being curved. Also, the box under the desk is a radiator box and is the only support for the desk besides the back cleat (is that enough?). I want two things; one, how to build/ tips and tricks on rad box; 2, any ideas on how to design it better (I really want to refrain from putting a leg under there as much as possible).

Thanks sooo much for the input it's much appreciated!

Images: http://imgur.com/a/8esB3

Edit: I for got to mention the desk is 7 foot long (3 on rad box and 4 on cleat) also 2 foot off the wall! ty