My parents have a Leylandi in a corner of the fence. My brother and I had a 'den' in there. One year my grandfather tarmacked it - it was meant to be a lovely surprise for us, to make the place easier for us to play in, but it totally destroyed the magic for us and we never played there again.
Another magical thing for me was that my mum grew masses of food plants, but not necessarily in any order. There were vegetables and berries among the roses, for example. We were alowed to pick whatever we wanted, and I loved playing in the garden with schoolfriends, and 'grazing' together.
She also planted many of the cut-and-come-again type plants, like geraniums, so that we could pick them without doing any harm to the plant or the overall display.
I'm at a similar stage to you with our garden .