Looking at taking a group to BPW for a day, overnighting, and riding somewhere in the same region on the 2nd day.
What's best within 30 minutes or so of Crickhowell? Probably looking for a 3 hour ish ride.
Afan probably has the most options for a group. Everyone same abilities or mixed?
Given how Afan is at the moment, go to Brechfa instead.
Forest of Dean uplift.
Does it have to be a trail centre?
http://www.justgoride.co.uk/Content/Routes/Viewer.aspx?id=1119
Doesn't have to be a trail centre, and will probably be in March/April. Have to plan ahead!
Group will be decent riders, well capable of a 3-4 hour red/natural ride.
Brecon Beacons / Black Mountains Killer Loop. With a few extra bits if the weathers good.
[url= http://www.mtbbreconbeacons.co.uk/hubs/talgarth/grwyne-fawr-reservoir ]Route[/url]