I do take 24 hour calls for pediatrics, yes. It tends to be part of the job for rural community hospitalist. Whether that's a reasonable workload depends entirely on the volume of calls and call ins, which unfortunately is hard to estimate from the outside as it depends as much on the hospital culture as the census. If they are calling 10 times per night and calling you in once a night then its a nightmare and they need someone in house. If they are calling twice per week and calling you in once per month then its a smaller price to pay. Even if the workload is reasonable a lot of people aren't comfortable with the nighttime responsibility. If you need a drink to relax at the end of the day, or if you have hobbies that aren't compatible will call ins (rock climbing, long bike rides), or if you just feel really nervous when you're holding the phone you may prefer a more traditional 12 hour shift gig.
If I were considering this I would insist that they have the ER cover some major holidays in addition to your 6 weeks of PTO: Christmas eve and Christmas, Memorial Day, the 4th, Thanksgiving and Black Friday, and New years eve and New years. Otherwise you might find out that locums is never actually available to cover those days when you decide that you want those days off. I suspect they would negotiate this.
If they did that, 6 weeks PTO + holidays = about 17 days per month. With no weekends or holidays hat's not a bad hospitalist gig. There are still plenty of people who would rather work 12-15 days a month and deal with the weekends/holidays, or who would refuse to deal with the night coverage under any circumstances. I don't think you would be a sucker to either take this or to leave it.
One other question about this job: is someone going to be available to cover if you are sick? This definitely doesn't sound like the right job for someone who calls out every month, but its a big disadvantage if you can't even call out with the flu once a year.