I travelled to Heysham Port last year - was the only passenger on the train between Morecambe and Heysham in both directions.
On the way back to Morecambe, the service was disrupted - some children had managed to access the running line from a bridge which caused a short delay. The train eventually continued - as we went past the children were still on railway property, trying to climb back up to the road and sliding back down towards the line. They must have been extremely bored to plan that into their day.
As for rail replacement buses, generally speaking I think the procurement departments do liaise with the bus operators and provide maps or at least coordinates for the stations. But the bus driver still might not necessarily know where they're going - if the bus has been called at short notice, it might be a case of any bum on a seat for a driver, someone who hasn't previously learned the route. I can attest that joining the dots with postcodes is not a good way of doing things. The last time I did that when route testing ahead of going in service on an emergency job, I ended up driving through army land and onto a route with a 8'9" bridge - fortunately I found a safe place to turn not long after seeing the warning sign. On receiving a map a few hours later, the prescribed route would most certainly not be suggested by a sat nav.
I'm not convinced it's an easy issue to fix hence why there are SOS tweets from passengers on lost buses or at intermediate stops the bus has missed pretty much every weekend - this is a nationwide thing, not necessarily limited to one area. There are inherent challenges with training people on routes that may run only run every few weeks or months. There's no guarantee the same staff with the route knowledge will always be available to do it. In this area, a limited supply of pilots are paid for who are meant to show the driver the route. But the buses still get lost with a pilot on board and we only find out because there's been a collision with a bridge or parked cars, or the vehicle has gone missing for a noticeable amount of time. Sat Navs aren't the panacea either - certain routes you know when the driver has been using one in lieu of proper knowledge because they've ended up down a road with a 6'6" width restriction, or a low bridge. If the driver misses a turn, the new route suggested by the Sat Nav might not necessarily be a safe one.
Diversions are a problem as well - it's not unknown to find level crossings down or bridges blocked part way through the day and such obstructions can throw things well out of kilter.