I would recommend Edinburgh.

Check out the castle website it looks to be quite informative

Hi. It’s a great place with dedicated costumed staff making it more realistic to children. I think there are a lot of displays really aimed at them. As far as the access is concerned, I think there are no particular tips to give. We went on our way up from Glasgow to Loch Lommond. Enjoy.

If you are pushed for time an hour will do but 2 hours is better. But this also depends on the weather as we wandered around outside in glorious sunshine. You may not spend so much time looking at views if its raining.

yes if you want

You can spend a good hour or 2 at the castle a very lovely day out and staff are very informative and helpful.

yes you can

There is few places where you could possibly take your dog with you like Old Stirling Bridge, Cambuskenneth Abbey, Mar's Wark, Beheading Stone, Wallace Monument or Cowanes Hospital, but I'm not sure if they are interesting enough for you. And that would be quite long walk to see them all as many of them is scattered to the north-east of the castle. In case of abbey and monument, they can be found on the other side of the river. To see just them three ( bridge, abbey & monument) you would need, roughly, around three hours, but obviously, they are not as good as castle. Between the castle and Holy Rude there is old cemetery and, to the south-west of it, you can find King's Knot - earthworks that use to be part of gardens of Stirling Castle.

Knowing a bit of background history about your venue, brings to life what you know, as you stand in its place. When visiting any Castle really, be prepared to walk up and down steep stairwells, might even be damped and cold (depending on time of year), lots of uneven and sometimes crumbling ground, dark areas and maybe lots of tourists trying to take a photo of the very thing you want to photograph! Bring comfortable shoes, season appropriate clothes and a lot of patience. Visiting a Castle, any Castle anywhere really, for the sake of going may not be much fun. Bring your imagination and you’ll love it! Happy travels.