Both my husband and I work fulltime, we have a son, who is nearly three.
Our son goes to fulltime nursery, he loves it. It is expensive though - for us (we spend £1000 a month on childcare), our combined monthly take home pay is around £3500, so a good chunk of it goes on nursery fees. I only mention this because it's a big expense and we do struggle financially - so much so that we've decided that we can't afford another child (
).
I work 5 minutes walk from my home, so similar to your (potential) situation. This makes it so much easier! It does mean that if our son needs to come home from nursery because he's ill, it's me who collects him - but my husband (nearly) always organises to take the next day off to care for him, and we take it in turns so neither employer can get the hump (well, they do, but they also have to be reasonable as do we).
Working so close to home means I can pop back on my lunch break and do some odd jobs round the house (laundry mostly, washing up or hoovering), but not every day because that's just exhausting! I did get a bit pissed off with doing all the housework, so ranted to my husband and now we take it in turns on the weekend, where one of us will take our son out for the day and the other cleans - we do this most weekends, and have a rule that we always have one family day each weekend that we spend together.
This is what works for us. Everyone is different.
If I was you, I'd take the job you have skills in. You'll get a better pension, with it being full time, and I expect it would be more fulfilling if you already have experience in that area - work has to be worthwhile for you to send your child to nursery (i know this because I stupidly took a job that I didn't want, and was a long way away and it was not worth being away from my boy for - I lasted 9 months and was a sahm for 6 months before getting my current job because I was much more picky about the jobs I was prepared to take - even though we we're seriously screwed financially during that time). Being close to home means you can get back to the children should they need it (but do make sure your other half pulls his weight on this front, or you may not last long in the job!) You could even do what I do, and pop home to do a bit of housework to minimise what needs doing outside of work hours. Up to you.
I don't know what it's like once the children are at school though, but assume that after school clubs exist in your area and you could look into that for your older child? That's my plan for when the time comes!
Best of luck, whatever you choose to do.