In reply to Hollie88:
Some good advice already. Here's more how-to stuff:
Tips for Walking with Kids: https://www.ukhillwalking.com/articles/skills/series/children/are_we_nearly...
Top Tips: Camping with Kids: https://www.ukhillwalking.com/articles/skills/series/children/top_tips_camp...
The first article includes a list of suggested hills at various levels of difficulty.
Of these only Ben A'an is close to Glasgow: https://www.ukhillwalking.com/logbook/r/?i=1256
Other mini adventures on your doorstep could include:
Dumgoyne https://www.ukhillwalking.com/logbook/hills/dumgoyne-30540/
Conic Hill https://www.ukhillwalking.com/logbook/hills/conic_hill-12552/
Then a bit further afield you've got things like:
Benarty https://www.ukhillwalking.com/logbook/r/?i=451
West Lomond https://www.ukhillwalking.com/logbook/r/?i=140 (though perhaps via the easier route from the east)
Arthur's Seat - if you're in Edinburgh for a day trip anyway then don't underestimate what a great wee hill it is, plus child-friendly. The summit will be heaving but there are lots of less-busy corners and routes in the park.
Pentlands are good for family walks.
Post edited at 09:29