I am planning an approximate 6 week solo trip to Europe in January and February. I know the weather is colder. I know the sightseeing hours are shorter. I will work with what I have.

I need some advice on the tail end of my trip. At the end, I will be flying into London and spending approximately 5-6 days there. I planned on continuing onto Ireland, but have now decided to include an extension through Scotland, on into Northern Ireland, and finally ending in Dublin before returning home.

I usually like to base myself in a city, stay in a mixture of hostels and B&B's, do a couple day trips, sometimes using tour groups, other times using public transport on my own. Sometimes I stop somewhere for a day on the way to my next city base. My main interests are history, art, architecture, and ancient sites. I have no interest in tourist traps like Loch Ness or the Blarney stone. The actual city of Edinburgh looks enticing, along with Stirling Castle, and some kind of taste of the Highlands. I definitely want to see the Giant's Causeway and Newgrange.

I will not be renting a car. It's too expensive, and far too much of a hassle for me on my own. I have plenty of experience using public transportation. I know the limitations and can live with them. Ideally, I'll enjoy either Scotland or Ireland so much, that I'll return at a later date with someone else, rent a car, and have more flexibility. This is not that kind of trip. I like a mixture of slow and fast paced travel, but believe me, I will have my slow moments at other times, so no judgments please.

I was thinking that I would take the train to Edinburgh from London. Spend 3-4 days in Scotland, then fly with a low cost carrier from either Edinburgh or Glasgow to Belfast. Spend a couple days in Belfast, and then continue on to Dublin for the remainder (approximately 4-5 days).

Any advice, on which city should I base myself in Scotland? Should I combine two cities? Is one city better than the other for day trip tours?

Any recommendations for day trips in February for both Ireland and Scotland based out of a city?