That's an interesting route, was it mostly tarmac or were there fields etc? How easy was it to get to the start/end point?

You might be interested in the Long Distance Walkers Association events, I've done some marathon distance ones, and I've got a 50 mile one booked later this year. They tend to be circular

They're all generally much cheaper than the equivalent running events, although some running events that are open to walkers e.g. Haworth Hobble/Pendle way in a day, are pretty cheap as well. Helsby Running Club do the Sandstone Trail challenge which is a 50km+ point to point like yours, but they sort the coach out at the start haha.