For some reason the 2-6-2 tank is not very well supported in the Model Engineering world. I do wonder why as I personally think that a large tank would be an ideal club track loco.
Reeves have Trevor Shortlands highly detailed design for the GWR large prairie. This has a very good reputation but not really suitable for beginners.
Martin Evans GWR small prairie "Firefly" should be fairly straightforward but not very well supported by the castings suppliers. Most of Martin's designs are practical locos designed to be used rather than being scale models.
Enterprise is another Martin Evans design but is a three cylinder loco with the complications of an inside cylinder and a crank axle. It could be built as a two cylinder engine, I suppose, but this maybe goes against the grain.
One thought; you may like to consider Martin Evans "William" design for 31/2 inch gauge which is specifically designed to be relatively easy to build and is very well supported in the trade.
regards
Adrian