Unfortunately I've never had the privilege of travelling on an overnight train, so the longest train trip in terms of distance travelled and time spent that I've travelled on was a Hotham Valley Tourist Railway diesel-hauled day tour train to the Western Australian Wheatbelt town of
Wickepin, back in 1994. Although it's only 214 kilometres from Perth as the crow flies, the journey by rail is substantially longer as it is not direct (probably around 300km or so).
Because of this, the trip there and back took most of the day (not not mention speed restrictions on the branchline to Wickepin added to the journey time too). As well, the return trip took substantially longer than the forward journey, on account of an hour spent waiting at a siding for a crew change, the fresh crew arriving by car (in those days tour trains were driven by Westrail crews, hence the need to wait for a replacement crew).
By the time we finally arrived back at Perth City station, it was nearly midnight, by which time suburban services had already ceased (due to it being a Sunday night), and the station was in the process of closing for the night. Still a great trip either way.
As for times spent on the train, well, it's been many years since then so I can no longer remember exactly, but I think we left around 9:30am, arrived by 1pm, and departed on the return trip around 5pm, arriving back at Perth at midnight. So, I spent a good 12 hours or so on that tour.
