I have been feeling pretty good on tx and had a family reunion i wanted to go to. I waited till i started tx to see how i was feeling then i booked the flight. I took my 6th shot in a hotel room, it was not that bad. But i would wait to see how you are feeling.
In my opinion, it is unpredictable. Early tx certainly be cautious as you get used to everything however each week is a different experience. I would say go just plan for low energy and possible sx such as dizziness so not a lot of physical expectations. The sun is a problem for some -- if you can be flexible and just have a relaxing time it might be just what the doctor ordered :)
You can travel. Remember to to have ice packs and a way to keep you injectables cooled. I didn't feel like going anywhere but home while on tx. I canceled plans for travel during tx. I know now I couldn't do it physically or emotionally. I could only do what was absolutely nec.
Judy