Crackpot Cave, Swaledale
Original Main Entrance now collapsed, so the (unfairly named) Kneewrecker Entrance must be used instead.
Very pretty as far as the Turnip Field, which involves passing through Column Chamber, but not much is worth continuing for beyond there.
The trip is very short and can be done in under a couple of hours, but leave much longer for callout due to the distance which must be travelled back before signal is reached.
Suitable for novices.