Now that I understand the back story and intricate connections, carry on.
I will make the following suggestions in an effort to make the project better and longer lasting/less maintenance.
Rather than painting grab irons, stirrup steps, etc that will likely be very seldom used and more for effect, I would recommend having them powder coated. Powder coating will stand up to the sun longer and remain looking good doing so. Powder coating will also seal the metal and eliminate rust streaks. Over time, you will recover more than you spent on it in saved time and materials painting again.
Fasteners to attach the grab irons, stirrup steps, etc would benefit from being stainless steel (316 recommended). SS will again eliminate rust staining over time. Fasteners that are part of the brake rigging, or draft gear I would stick with high grade steel for the strength factor.
Being as this is not a restoration as such, I would highly recommend a rubber underlayment under the roof. After Hurricane Michael damaged my roof and caused it to be replaced I decided to splurge on the roof and install the rubber membrane. NOT SORRY I did. Well worth the extra expense.The membrane causes all the sub roofing materials to be effectively joined as one making it structurally stronger. The rubber itself acts as a sealant when nailing the roofing material down, and if the roofing material is damaged will continue to hold water tightness.
Yeah, I am spending your money, but offering food for thought.
Interesting floor plan for a 210-250 sq foot space. Definitely COZY.
FWIW
Bob C.