If you really, really, want to be bored shitless by my 40 year obsession with that line you could always join me.
https://brightonlines.wordpress.com/2014/01/03/in-search-of-hartington-road-halt/
Not sure where you are getting those two from.
The tunnel, as you correctly say, ran alongside Elm Grove School and under the Down Terrace/Pankhurst Avenue junction. It would have wheeled under Freshfield Street and just east of St Luke's School. That brings it out around Evelyn Terrace.
Depends where you live really. Urban scenery can be just as captivating as rural.
I work in the harbour at Portslade and walk back to Queens Park many an evening. I walk from the office along the beach path from the far end of the lagoon to Palace Pier. That's about 3 miles with just under a...