Staying in Donegal town for 5 days. Thoughts on going south to Sligo or north to Derry? Then returning to Dublin to fly home. Traveling by bus. Late May and relay June.
Do you have particular interests, like sights associated with W.B. Yeats, or Neolithic tombs, or scenery? We were in the area last September, but with a rental car, and were mostly touring the countryside, with limited time in cities.
We drove through Donegal town on the way to somewhere else, so didn't experience any real time there. We stayed 3 nights in a B&B outside of Sligo town (on a very narrow, winding road through farmlands), but, again, didn't spend much time in the town.
Derry, however, was a pleasant stop for part of a day. We were there on a weekend, when they had a foodie festival in the square - great fresh oysters! It was interesting to walk the old town walls, from which we viewed some of the famous Bogside murals in the near distance, but we didn't go and see them up close. Derry was a nice taste of Northern Ireland, without the intensity of busy, very urban Belfast, which we visited a week later.
I enjoyed Sligo. It has some pleasant walks along the river and several enjoyable sites to visit. I’m a big W. B. Yeats fan, so visiting Yeats’ sites was a major interest, including enjoying the views of Ben Bulben. The Yeats museums in Sligo are good, but not up to the level of the museums in Dublin.
The Derry city walls are impressive as is the Peace Bridge and the Bogside Murals. The Guildhall Museum is well done and informative about Irish history. There are walking tours of the murals as well. I met a couple who did the tour with someone who had lost an older brother during the violence commemorated in the murals.
The choice of either depends on your interests, but my main reason for Sligo was the Yeats connection even though there are other reasons to visit. Derry does give a good perspective of Northern Ireland.