What works for you depends on whether you're a fast whippet or a fuller value rider, and how well you get on with little/no sleep.
My 1000km perm ride was an out and back, though I started about 1/5 way along which I split into approx 560km and 440km with a 12 hour break at a B&B
thus
day 1: get train to start, have lunch, start after lunch and do 220 approx km (1st 1/5) and have 4winks in the small hours in same 24 hour cafe
day 2: continue until I reached the B&B about 7pm (with leeway in either direction) and sleep, thus getting max use of B&B, unlike, for me, booking >1 night
day 3: start about 7:30am after the brekky and keep going (via crinkly cateringtm at late lunch/high tea o'clock) and keep on via coffee-with-students in a 24hour mcd accepting pedestrians
day 4: continue until i get back to the start in time for lunch, eat and go home, again on a train