I had a three bedroom seaside flat sleeping 8 - one double bed, two single beds, one bunk bed, and a double sleeper sofa in the sitting room. I switched from holiday let to full time rental - less money but definitely less work.
When it was a holiday let, changeover day was fixed as Monday or Friday, three night minimum. So a 3 night weekend, Fri - Mon, or 4 night midweek, Mon - Fri, or one week either Mon - Mon or Fri - Fri, etc. No deviating from Mon or Fri, they could leave earlier or arrive later as I had a key safe, but still paid the full booking.
I did changeovers myself, took every bit from 10am check out to 3pm check in. I had 4 sets of linen for every bed, and 4 sets of towels - each guest got one bath and one hand towel for short breaks 3-4 nights, and two bath and one hand towel for 7 or 10 nights. There was a washing machine they could use.
I made it a one week min over Xmas week and NY week with a triple deposit - bugger the person who wanted to check in Xmas Eve and leave Boxing Day, no way was I ruining my own holiday! Likewise NY weekend partyers! Pay the full week and big damage deposit or go elsewhere.
As I said, I made a lot of money as it was fully booked May - August, and I had several 10-21 day lets over the rest of the year from contractors working in the area. But must emphasise it was a lot of work, and when someone who'd stayed for 10 days asked about a 6 month let, I jumped at it. During that time they made an offer to buy, which I accepted, and it went through, sale fully completed, three weeks before lockdown started!
You get a lot of tax breaks on a furnished holiday let, so I doubt OP will have many taxes to pay - in my time, the offsets just about equalled the income, so with no other job, I didn't pay much tax. Your petrol to and from, wifi for bookings, printing ink and paper etc etc are all chargeable offsets.
I also charged for my cleaning time - got three quotes from professionals, and used the lowest rate on my tax form.
So if OP gets the museum job and runs the holiday let, even allowing for the occasional professional clean when she's not available, and childcare / ASC when neither adult is available, she should still be better off. That's both financially and MH-wise.