Adorable build! The barn red and white accents are pleasing.
If you really want something durable you may want to start with a locking lid on hinges with a strong lock for the pen area to keep out stray cats, stray dogs that break in (like we had), aerial predators, wandering wildlife (that you never knew you had until you get chickens!) Since you're in PA you probably get snow so a slightly tilted pen roof would probably be helpful for snow cleanups. As for the ground we never put anything on our dirt floor pen but then we're in SoCal with no snow - we rake up the dirt to collect for the compost pile but because we free-range days the girls don't use the coop much. I love your lattice finish but would suggest a hardwire (1/2 inch) interior walls to keep manipulative wildlife paws from reach through the white slats. I know your coop is still in progress but just throwing in some security suggestions before you "finalize" your build. Also provide a portable little perch or tree branch on the ground in the pen to keep the chickie tootsies free of wet or muddy ground - plus they love perching even on low little perches all times of the day.
Not sure what your space requirements are since what you have might be comfortable for only a couple bantams - unless you provide some more space with supervised free-range time for your birds every day. Having a chicken pop-door open 24/7 is not safe as predators will climb in at night into the coop like someone's loose pet snakes, rodents, maybe even oppossums, weasels, or raccoons that you never knew lived in your city. Don't know where your people door is located for coop cleaning but I definitely see an issue with needing more ventilation holes near your roof line. If you drill some ventilation holes cover them over with hardwire to keep out rodents/snakes. A paver stone walkway around the perimeter of your pen will discourage digging critters- it kept dogs from digging under our 4x6 coop 3 years ago - but of course they mangled the chicken poultry wire with their teeth and claws which is why I suggest using only secure 1/2 inch hardwire and not flimsy poultry wire which tears apart from itself.
When you get on this thread there will be a lot of experienced advice thrown your way. We all love our chickens so much we want to do everything possible to pass along security suggestions. You'll probably get more suggestions than this. Post your finalized project again as we love photos!