There isn't really space inside the walls. The walls are designed to be earth filled and absorb the shock of solid shot. There are two narrow passages leading through each of two "skinny" curtain walls (no cannon on these curtain walls). I stole this idea for the narrow passages from the Last of the Mohicans (book and movie). The long thick unfinished curtain wall will support four gun embrasures (top of the lower photo, Post 26). This thick wall would have been entirely earth filled without casement storage. Any artillery attack is expected to occur against this wall or against the gate wall. The gate curtain wall will support 3 embrasures.
By shrinking the fort to 225 feet per side (instead of the desired 300 feet), I needed to eliminate the casemates (interior/underground storage) on the "non-attack" walls, otherwise the parade ground shrinks even further.
There are no loopholes in the walls. The holes you see are for defensive stakes. You can see a few in the first photo, lower right corner (Post 26).
There is a door leading into the each of the bastions, but these end after a blind turn. Three of the these bastion doors are already in place (really not visible in the photos). The fourth bastion door will be part of the ramp/staircase connecting the parade ground to the rampart. So with six doors along the interior of the parade ground, there will illusion of at least some underground storage under the bastions.
Any help on the gate would be much appreciated. I have rejected all of my previous gate ideas, so the slate is clean and the cupboard bare as it regards the gate. That side of the wall isn't visible in the photos, but immediately beyond the limits of the gate, there is a vertical drop of about 5 inches into "the ditch". The idea was for a drawbridge.
Barrack construction is another totally slate. I am open to any ideas including stone.