Hi! I need some advice, please.

I have a very pregnant stray cat outside. I've enclosed my apartment's
patio (with her inside the patio) to keep her safe from the tomcats, and
my plan is to get her and her kittens fixed as soon as it's safe to do
so and find them homes. I can't bring her inside because I already have
cats, and not only are there the health concerns but there is also the
space concern (one bedroom apartment).

Here's the problem. On my patio, I have a 2x2x4 kennel set up with part
of it draped to try to provide her with a little den where she can hide
and feel safe. The lady who just catsat for my indoor cats told me that
I need to do something differently, because the kittens could slide out
through the openings all along the sides of the kennel and get separated
from the momma cat and die.

Here's my difficulty.. I live on the Gulf Coast, and it's REALLY hot
outside most days. I'm reluctant to set up a mostly enclosed box for
her, because it wouldn't get any air circulation.. I'm worried that it
would be way too hot for them in the heat of the day.

Before I go to work today, I think I'm going to make some strips of
cardboard and put them around the bottom of the kennel, going up a
couple of inches, and see if that will help.

I'm not sure what would be the best thing to do for her. Should I go
ahead and put a cardboard box out there for her? Would that be cool
enough for her? Should I maybe put something with sides inside the
kennel for her (like maybe a new, clean litter box or something)? What
would be likely to help her feel safe and keep her and her kittens safe?

Thanks in advance! :)