I was caught up in the possession on the Eastern Leg of the Elizabeth Line a couple months back and had to travel to the Seven Kings area. On my inbound journey, I connected at Custom House then used a bus to the Ilford area, followed by another for Seven Kings. On my return journey, I was faced with the predicament of using either the 86 which pretty much runs down the Elizabeth Line corridor to Stratford or use the rrb* apparently running every 10 minutes. After walking to the front of the station and seeing both options were delayed, I opened citymapper and noticed Newbury Park was nearby and walked through the residential streets to get there. I would pick this option again because the inbound journey was nauseating as someone that suffers from motion sickness; and frankly the sheer amount of people at the bus stop worried me. The Central line was dead quiet, longer than usual journey to Stratford admittedly with no 4g/5g connection but it was a much better experience; and an opportunity to use a line I don't regularly use. If faced in the same situation in the future, I would do it again, but only few areas of London (especially outside z1,2) are lucky to have stations on different lines in close proximity. - Echoing the points above that Newbury park is genuinely massive and is well suited for RRBs.
* = Something I will say that impressed me with how RRBs are handled in other areas of London, the RRB was appearing on the Bus Countdown attached to the Bus Stop as a 'RAIL - Stratford Station - 10 minutes' entry. I was really impressed, and I'm not sure how complex this is but it needs to be brought to other areas of London to raise the profile of RRBs. Another way this is accomplished is through the yellow banners that are attached to rrb stops. This is a no brainer and I don't understand why it isn't available at non-TfL stations. I will note that the image I have attached to show an example has Wood Street with the 'NR' symbol not the one TFL use for LO, so it could have been taken when the line was operated by GA, in which case perhaps it's more of an operator issue than a TFL one.
Timetables are rubbish when they come to RRBs. And inconsistent destinations compounds the issue; ie RRBs from Romford will always go to Stratford and not sometimes continue to Liverpool Street or Paddington etc. On my local line, RRBs will sometimes go to Lewisham, sometimes New Cross, sometimes Greenwich, sometimes London Bridge. It is so inconsistent and I'm not sure how anyone can expect passengers to reasonably grasp this information without constantly checking the Southeastern website. I wonder if TfL charges TOCs to add their RRBs to the local stop's countdown or it is accessible by virtue of operating buses in London? Or perhaps only available to TfL trains? The overarching issue is that there is no way of reasonably being updated on the RRB. At your large destination stations such as Newcastle or other prominent LNER stops, you can expect to see staff ushering passengers to and from the coach stop and they are available to advise on destinations, routings, and when the RRB will depart. That's not available - or to be expected - at your local suburban stations. Southeastern RRBs now sometimes update based on their location through NR data feeds (meaning it reflects in the SE app and apps of other journey planners). While novel, it's insufficient. Very few will refer to journey planning apps on a day when the trains are not even running, but all will look at the bus countdown of the local bus stop.