Paris to Scotland

If you want to maximize travel time my suggestion is to walk…

But if you want quick there are flights from Paris to Edinburgh.

Cheapest and quickest way is likely to be direct flight from Paris to Edinburgh.

You can fly EasyJet direct.

I don't know, but BA or Air France may have direct flights too.

It will be slower and more expensive than a direct flight, but the train journey from Paris to Edinburgh is pretty easy. Take the Eurostar from Paris to London, you will arrive at the St Pancras station. Trains to Edinburgh leave from Kings Cross station which is literally next door to St Pancras.

Both the cheapest and the fastest way is definitely by flying. EasyJet has cheap flights taking under 2 hours (plus time getting to and from airports). The train(s) will be substantially more expensive and take around 8 ish hours, allowing for station change in London.

We took that Easy Jet flight (opposite direction) a few years ago. It was quick and easy although you do get dinged with lots of extras if you want to choose seats, have checked luggage, etc. For those considering the train option, we have also used both of those train routes. Neither is especially scenic, except for a brief bit near Edinburgh. Scenery is similar to what you would see from a train crossing Ohio / Indiana.

Air France and Easyjet have nonstop flights from CDG airport to Edinburgh. Just under two hours. (Ryanair also flies to Edinburg but from Beauvais airport. That's a far distance from Paris.)

The train, with a 30 minutes transfer in London will take just over 7 hours.

Take a morning flight and with the time difference--the UK is one hour behind France--you could have lunch in Edinburgh.