The current plan is to bike around all of Ireland, including Northern Ireland. It's not fixed, but for now, it's the plan. I will take a train from Fulda to Paris and then Cherbourg, followed by a ferry to Dublin. I never traveled by plane with a bike and don't intend to do so this time. It seems too much of a hassle to pack the bike, unpack it, and pack it again. The biggest point not to fly though is the uncertainty whether the bike will be handled well. I was always flying with hand luggage only because I didn't want to risk my luggage getting lost. If the bike would get lost, that would be a catastrophe. Another consideration is, that I generally don't want to fly anymore, unless absolutely necessary. Caveat, I did not research whether the ferry would be better or worse in terms of emissions... I will book the ticket to Ireland quite a bit in advance, but will leave the return open. Needing to be on a very precise day at a very precise location is too strict for my liking.
I developed the first draft of the route on Komoot in a similar way how I planned a week on the longer trips. Simply picking a start point and adding points to the route. This sometimes works, sometimes not. When Komoot is really persistent in sticking on an endpoint I have to start again. Once the rough outline is there, I pick additional spots on cycle routes to force it to certain paths. Once this very rough draft is there, I save it as trip and plan then the different stages. Komoot is really good with that. In this case I divided it into 30 days, which leaves me each day with roughly 80km. Enough to make it in a month, but not too ambitious. The total distance is around 2300km.
This will be then the base to search for accommodations. I will be biking in April, meaning the weather is going to be not too warm. According to google though, April seems to be the driest month in Ireland. I will pack my camping equipment, but will definitely give Warmshowers a try. This trip will be far less flexible, which means I can easily contact people beforehand. I'm quite curious whether this will work out.
That is enough of a plan for the time being. Once March has come, I will look into more details.