Hiya,
The likes of Cwmorthin, Wrysgan and a few others can be happily explored for many an hour without the need for SRT.
Wrysgan will give an hour or so thru trip or you could wander off track and take a bit more time.
Cwmorthin you could be underground for many many hours some SRT is possible but it would probably be advisable to get a feel for the mine before lobbing off down into a chamber.
BTW you will need the code for the padlock for Cwmorthin.
Needless to say, once you come round N.Wales, you'll be back :thumbsup:
May the fleas of a thousand camels infest the crotch of the person who
screws up your day and may their arms be too short to scratch.