I know that sounds like an oxymoron. 
We're spending August in Edinburgh, like half of the UK, and I will be doing a full-time course Mon to Fri. I have almost 7yo DD and 3yo DS to keep occupied on the weekends, but they are not super keen on crowds. We will be in Newington, and much as I love Blackford Pond I probably can't cope with going every single day.
Are there any other places I could take them. Please not the zoo, we did it last year and I was ready to kill DB, a nephew and at least one DC.