Let me look at a map… maybe 1km max anywhere in my 30k town to the next primary school and that’s when you’re living on the very very edge of town. Should be under 500m for most pupils.
If you’re living in a rural area, outside of the next village (which will have a school), which is an absolute exception as things tend to cluster into villages in rural areas, it might be 5km. Not really an issue with a bike, I biked what 3.5km to Kindergarten (together with my mom). If you have less density than that you probably should have boarding schools.
For secondary education, if you’re living in a village you’ll probably have to take the bus to the nearest city. Regular public transport though the schedule will take school times into account. Yes, kids can walk 500m to the nearest station.
Bonus: All that school density – smaller but way more of them – means that there’s obvious places to hold elections as there’s a municipality-owned place in Sunday stroll distance to pretty much everywhere. The only downside are the ludicrously low tables.