100% must see is the Wallace monument in Stirling.
Ben Lomond on the east shores of Lock Lomond is a great hike for between 4-6 hours.
Holyrood and Inverleith parks in Edinburgh are very nice for an easier day out.

There are hundreds of great restaraunts in Edinburgh for all tastes and tongues but that's more of an objective subject so I'll have to leave that to you. Let me know how you get on