I am looking to purchase a Starcraft or an expanda. Like the idea of the ease - no set up except popping up the roof of the Starcraft but am unsure about the bunk bed height between the two bunks for kids age 10 and 12 it seems quite narrow. How have others found this with their kids. Also asked about changing the bottom bunk to a tri fold like the expanda and was told no does anyone know if possible to change. Thanks