I would be cautious without a fan. I did two workouts without cooling and then some without proper placement and had issues with overheating. At some point during the workout I felt like my head would explode and I was close to fainting.
Fans such as this one are small and portable but they generate enough airflow to cool at least your head and upper body. If you pack an extension cord, you can plug it into an outlet nearby. (link to German site for illustration - didn’t find the exact same model on amazon.com)
If you don’t have good cooling, you’ll always restrict yourself to the amount of heat you can dissipate rather than the amount of power you can deliver over time. It’s of course better than no training, but I’d try to get a fan into the setup somehow.