Seasonal hiring: what is paying well this year? - what worked for you?

I am looking at seasonal jobs around Madison that might lead to something longer. I am in Madison, in case local advice matters. I would like to avoid a gap in my résumé. Is it worth applying to several at once?

Keep a list of supervisors' names. A reference from one of them helped me land my next job.

Apply to several. Start dates and schedules change quickly and having options helps.