I've got several books on the 251 with a fair few photos of worn out winter camo schemes.
If you are after an easy introduction to skinning I would not go for a grey 251 however. The problem is you would need to do both the interior and exterior, as the default interior is brown.
Of the new planes and vehicles, the Las are probably the easiest. There's not many panel lines and not much rivet detail, as they were of mostly plywood construction.