You can generate income from the online business like selling products online or work as a freelancer and provide his services to client and they will pay for that service. rightnowcleaning
It depends on how you decide to travel. When I was a student, I got a job on a German cruise ship for the summer. I was an assistant in the cosmetology office (eyelashes, nails). You can look through this blog yourself to find out in detail. It was an interesting experience. Now I travel as an ordinary tourist (with my boyfriend). Now I can work remotely (photo processing). It seems to me that such a side job is appropriate for rest.