3 dc with ASD here.
I make a planner for school holidays - literally draw it up and mark out the days they are with me and the days they are with their dad.
I then plan out my days/weeks with a balance of days out and days at home.
So far these holidays we have: been to legoland (birthday outing) and been to London to see a show (Joseph) as well as a trip to London to see the elephants in Green Park. Plus mini golf with friends, and a huge long walk plus pub lunch after with same friends.
Coming up for the rest of the holidays we have:
Local National trust visits
More mini golf
Local castle
2 more theatre trips (one London, one local)
Bowling
Play dates with friends (youngest - both going to other peoples houses plus friends coming here)
Local park has a kids trail that we might wander around
Possible trip down to the seaside (would also include eg an aquarium trip, as dc ‘need’ something to do, not just wander about)
Middle dc has really been struggling with her dad suggesting days out, because he literally decides the night before and she can’t cope with the sudden thought of a whole day out so soon. All 3 of mine seem to benefit from the planner, which I start drawing up around May each year (or as soon as I know summer dates/timings for going to their dad’s).
Not every day is set in stone - only the big trips are actually planned on specific days. Local stuff like bowling/cinema/mini golf is planned to happen, but not necessarily on set days. Eg this weekend we have relatives visiting, and we will be bowling on one day, and doing mini golf on the other, but still weather watching to see which way round would work best!
Local library often features for my eldest too - ASD with learning difficulties, so she still enjoys doing the summer reading challenge. And the time when I take her down there gives the other two some downtime to chill without constant trips/being out of the house (it’s my eldest who needs to be constantly occupied, hence many planned activities!)