Apologies, I've been meaning to reply to this thread for days.
When are you here - if it's during the festival (August) then there is a gazillion extra shows etc etc to do/comedy etc etc. Crazy busy but good fun and the bars/clubs are all open much later too. Nothing is cheap though!
I've never been to the witchery, it's a cut above what my disposable income allows... (and I squander that on chips, just don't tell Mrs hod). But yes it's one of the top restaurants in Edinburgh.
If you like Thai food, I'd really recommend Chaophraya (I think I spelled that right) - great restaurant and if you're organised enough book in advance for views straight over to Edinburgh castle. Took my wife there for our anniversary.
If you're not making a distillery tour, there's several whisky bars/societies in Edinburgh, many in really nice surroundings. Not sure if this is the one Toby was referring to or not -
https://www.smws.com/queen-st
I don't like whisky, so I can't really comment!
There's a lowland distillery (Glenkinchie) only about 45 minute drive to East Lothian if time is an issue. Glenkinchie is a bit marmite though, people seem to love it or hate it.
As for the rest of Scotland, I'd recommend going up the West Coast, Skye direction for some stunning mountains on the way (Glencoe particularly), and white sandy beaches when you get there. Just don't expect to be cutting about in your speedos when you get there.
Plenty of golf in and around Edinburgh if that's your thing, and historic borders abbeys in the likes of Melrose if you go that way.
Edinburgh Castle is interesting but if you like ancient places, Craigmillar castle in Edinburgh is far less sanitised and touristy, more interesting in my opinion (not a museum as large parts of Edinburgh castle are really).
You'll be fine with the driving, Edinburgh's traffic is pretty bad so you won't go anywhere fast. Parking is expensive and a PITA too, so if you're central I'd imagine you wouldn't use the car much at all, unless you're leaving the city.