I spent years working in the area on several contracts over the DLR, but have never visited Bow Church (the actual Church). I have always assumed the Church wasn't open outside service times and see nothing on their website to the contrary.
I've seen the transformation of the area, generally for the good.
Because of the nature of our work I was actually track trained on the DLR- trained to walk on the tracks- a very different task to being on National Rail tracks. I only ever had to do so once, in an emergency situation when we accidentally dropped a large object on live tracks. The platform link to the control room failed to work, and with a train approaching non authorised action had to be taken to prevent a potential derailment.
It is very easy to visit the area if travelling between the Tower of London and Greenwich- take the District Line from Tower Hill to Bow Road, walk along the street, then board the DLR at Bow Church. The two stations are an OSI- an Out of Station Interchange- so it counts as a single journey- you have up to 15 minutes from swipe out to swipe in to transfer- more than adequate to do a quick recce.