Hertford area, 3.5 years old, any tips for the summer?

So far my Son is getting on really well and starts nursery in September but I would like as much help and advice as we can get. He is funny, cheeky, good natured and likes to play and sing, at circle time the nursery staff had to stop him answering all the questions as he is very bright with labelling, colours, numbers, alphabet, I mean he could count to 50 when he was 2.

He was diagnosed at the start of the year but we had private care in place for about 6 months before the final diagnosis and my wife and I work really hard every day to get the most out of him.

We would love some hints and tips to keep him going over the summer, any groups like music therapy, play therapy, behavioural therapy, days out, he loves steam trains.

Best Wishes,

Neil