Review and Organize
You probably collected a lot of information while you were travelling. Take the time to sort pictures, photocopies, artifacts, and other things you have learned or acquired during your trip. Your future self will thank you for having the information handy in whatever filing and organizing system you have.

Review you to do lists, research notes, journal. Flesh out any ideas that may not seem clear while the memory is fresh in your mind.
Transcribe and Record
If you have acquired copies of documents, start transcribing them. This may feel time consuming and less exciting in the moment, but it will be incredibly useful for your research later. Start with what ever document or item feels most important to you. It could be a will or a deed or a letter.
Reviewing these documents more carefully will hopefully lead to new information, clues, and ideas. Record these. Get started researching the new questions you come up with.
Start Planning the Next Trip
Whether you return to the same place, or choose a different one, keep lists of items that are available in the repositories that are applicable to your research. When your ready to travel again, you’ll be prepared.
I hope to return to Ireland soon, but I also have Scotland and Germany on my list of places for genealogy travel.
You can read about our adventures in my Ireland Genealogy Trip series.