Welcome Aboard
if you can post some more photos from different angles of the
boat's bow section, someone could draw a diagram for you.
I would make a bow deck lid like the vintage runabouts that have
a full aluminum deck that comes back to the front seat so the
seat could be used as a step to get onto or off of the bow deck.
this would be a single sheet of .080 or .090" aluminum sheet
that is pop-riveted to the gunnels with 1-1/4 x 1/8" square tubing under
the deck lid for support. 1/2" plywood would also work well with the
same bracing underneath. you would also have to build a tray to hold
the batteries safe, secure and level.
there are literally hundreds of builds very similar to what you are wanting to do......
look through the build and mod section to get some ideas and what materials to use.
https://www.tinboats.net/forum/viewforum.php?f=21
if you go with wood, do not use any pressure treated materials
that will come into direct contact with aluminum.
the difficulty will be in correlation to your skill set and tools on hand.
a couple of examples
.