If you want to avoid changing your wheels, brakes, and axles, then the 380/15's are a good middle ground. They are notably bigger than 500x5 but not as big as 600x6.
One caution, if your wheelpants were installed with tight tolerances, the 380/15's May rub inside the wheel pant at the top or back.
I was reasonable fortunate and had internal clearances for the 380/15 tyres. I did need to increase the bottom opening a bit with a grinder and sanding block for the tyres.