It will all be revealed!
I suddenly realised that there might be something about the Land Cruise Trains in one of the Foxline books on the railways of North Wales, and there's a whole section about them in Bill Rear's book about the Corwen to Rhyl line
They started in 1951 and in that year was called The Festival Land Cruise; it ran clockwise Rhyl – Rhyl Monday – Friday in the peak season, and was so popular that in the following year a second train started. This started from Llandudno, and ran attached to a Crewe service as far as Rhyl; after being detached, the land cruise portion reversed and followed the first service round the loop as far as Llandudno Junction, and there was a further reversal to return to Llandudno. These were described as Radio Land Cruise trains and a radio commentary was provided in each vehicle
During 1953, the two services continued but were marketed as The Coronation Land Cruise; these continued in 1954, but because of their popularity more services were added. On Tuesday and Thursday there was a Pwllheli start which went round the loop in an anti-clockwise direction, and a fourth service started from Llandudno Junction on Tuesdays, Wednesdays, and Thursdays and followed the Pwllheli start around the loop, before terminating at Caernarfon. The following year it ran Mondays – Fridays.
In 1956 there were some changes; the Rhyl start continued around the loop clockwise, but the Llandudno start reversed at Barmouth Junction – that would have been interesting to see from what I remember of the track layout! – and then went to Aberdovey; after a break of nearly two hours, it returned to Barmouth Junction and then continued clockwise round the loo and back to Llandudno. The Pwllheli train ran as in the previous year, but there is no reference to the Llandudno Junction starting anti-clockwise service in any publication found by Rear, and he presumes it must have been an early casualty.
In 1958, one of the Devon Belle observation cars was transferred to the LMR and given the name The Land Cruise Lounge; its Pullman emblem was replaced with a BR crest, and it had to be turned at the end of each round trip. Then it all gets very confusing; but there's nothing at all about Chester starts. There was, however, a Rhyl start anti-clockwise working in 1960 called the Welsh Chieftain, and 1961 was the last season that the cruise trains operated.
Rear also mentions a service which operated in the 1960 season and was called The Clwyd Ranger; it was an afternoon DMU working on Tuesdays and Wednesdays only, and ran between Llandudno and Corwen, with a reversal at Rhyl. I remember the Welsh Dragon DMU service which operated between Llandudno and Rhyl, but I can't ever remember seeing The Clwyd Ranger
It's interesting that these lines (the Llanberis branch was another) continued to be maintained to passenger standards after local services stopped; I can see the logic if they were to be used as diversionary routes, but this doesn't apply to any of these lines.
In the book about the Ruabon - Barmouth line, there is reference to specials being run to Llangollen when the International Eisteddfod was on, and there is a leaflet about a DMU trip from Uttoxeter to Barmouth; no date is given for the latter, but it left Uttoxeter at 08.42, got back at 23.06, passengers had 5½ hours in Barmouth and it cost 17/- (85p in modern money). But as I said earlier, I haven't found any references to Chester starts
Hope this helps