I think there is viable merit in Mosney having some trains.
I remember a few years ago a clerk at Drogheda marking the trains which stopped there in pen on an A4 timetable leaflet for me. I don't think the services stopping there were publicised towards the end.
Many years before that at I recall the blue NIR loco hauling the Enterprise serving the station (think it was just one morning train that called).
There is a pleasant walk from Laytown along the coast to near Mosney but don't think it's possible to get from the beach/dunes to the former camp/station (no underpass to my knowledge).
I imagine it is possible to walk from the main road through the camp to/from the platform (maybe not actually onto the platform though). I have an inkling that there may be a special path through the camp to/from the station.
Ultimately will Mosney remain in its present role or is there a chance it may revert to a holiday centre? The nearby Funtasia opened in recent years fills some of the gap though. Trabolgan in East Cork is a similar centre that was opened in more recent decades.
Having only ever been in Mosney once (by train from/to Drogheda) it did give a pleasant day out. (I can't recall what ticket facilities were there as it's so long ago - possibly a member of staff was on the platform checking people were in possession of tickets).
The fact that Mosney's platform is on a loop off the two main running lines certainly has operational advantages.