Learn how to use resistance bands. They are not the same as free weights or machines but can give a decent workout if you do them correctly. They are small, lightweight and easily packed in carry-on. Also look at some Pilates classes for flexibility. Cardio is cardio - walking, walking/running stairs, etc can all be done in hotels.

It's hard to learn to be accountable to yourself. You can try wellness coaching which is different from personal training. At the end of the day, you have to learn to set realistic goals and find what works for you.