You need to be quite objective about this, and ask yourself what your priorities are.
If its fitting work around being able to drop off and pick up at school, then frankly, the work is likely to be menial and not stretch you mentally. Neither will the money be great. The payback is that you get convenient, short hours - and in your case, two days free to yourself anyway.
If on the other hand you want to use the skills and qualifications you have, and command a better wage and get greater job satisfaction, then you're realistically going to have to work more conventional hours, and arrange and pay for before and after school childcare, and holiday care. You are also more likely to have pressure in the form of greater expectations on you. It may be the sort of work where youre expected to stay on late, or where you can't automatically switch off when you walk out the door. The payback is the increased fulfilment and a better career path, pay, pension etc
This isn't being judgemental - there is no right or wrong, and indeed, one type of job might be right at the moment, but not in two years time. It will help to clarify in your mind WHY you are doing this though
I think your plan of taking it, but keeping an eye open for something better is a good one. If its really mindnumbing, at least the fact that you are on the look out will help. And its far easier to get another job when you are already in employment.
Just start to plan for the fact that the more interesting jobs with prospects are likely to require childcare, so it might be useful to start planning for this, so that if something else crops up in the hospital, you're not panicking and starting to think about these things from scratch.