Replying to Don’t Have Time for Summer Job

So this summer i will be going on vacation a lot and also taking some classes to prepare for college. I need money, but I’m worried I couldn’t hold down a job because of my busy schedule. I was also thinking of lawn mowing but I’d assume people would want their lawns done on a weekly basis, and with multiple clients, that might not be possible either. Anybody else ever have a similar situation, or have any ideas on what i could do