Hi Daniela,
It's great to hear you are coming to Ireland for a two week holiday, you will have so much to experience when here!
You mentioned that you would be travelling from Belfast to Derry. May I suggest you travel the Causeway Coastal Route between the two cities. It is a beautiful, scenic drive that takes in many attractions such as the Giant's Causeway, Carrick-A-Rede Rope Bridge, Rathlin Island and Dunluce Castle. There are also quite a few Game of Thrones film locations along the way.
You have asked about booking accommodation for your trip. If you wished to spend a night in the Causeway Coast and Glens area during the month of May, it might be a good idea to book accommodation in advance as it can be a very popular month for visitors. To find out more about the region, please take a look at our web site:
https://www.visitcausewaycoastandglens.com I hope you have a memorable two weeks!
Anne