I think with the roof hatch and two opening windows in the two doors there will be plenty of ventilation.
A roof vent fan which is common in some of the builds I've seen may be in order, depending on how it works out.
No other large windows were included as a part of the military look theme.
If you consider a lot of the classic teardrops only have the door windows, I have three extra.
They are approx. 4x19 and you can peek out of all of them.
-James