That looks to be a nice coop and a nice setting. One thing to keep in mind:bantams can fly better than standards, and some chickens are more interested in roosting up high, bantam or not. You might find that some of your flock likes to fly up to the overhanging trees. Because chickens are a flock animal, the rest will surely try to follow. Then, they are full-on free range...they've flown the coop. In a short period of time they can 'drift' from roosting in the coop at night to roosting in the trees at night. I agree with others that placing sturdy netting over the run is a good idea. This will also help to prevent predators from using any overhanging trees as a route into the run area. Hawks like to perch over prey, for example. If you cannot put netting over the run, then at least keep everyone cooped up for a few days once in the new location. But, be ready to address any issues that arise.
Last year, an acquaintance decided to start big with 50 chicks, who would free range. Once the flock could fly (they were all standards), they took to roosting in the trees during the day, and then at night. The whole flock was gone within 2 weeks, and the racoons were very happy until the food ran out.