Wheel-well stowaway is just about the worst thing you can do, ever. The wheel-wells are unpressurized, unheated, and designed to snugly fit the wheels in there

Wheel-well stowaway is just about the worst thing you can do, ever. The wheel-wells are unpressurized, unheated, and designed to snugly fit the wheels in there (airplane designers don't waste space!). If you're not crushed to death upon retraction then you're almost certainly going to freeze to death or die of hypoxia. Just don't do it.