In being a gunsmith of 40yrs and have made a living at it i was interested in your post. You have bitten off a big bite to chew. First off,you really have to have the desire,time,and most of all patience!Each area of gunsmith you have mentiioned is a speciality area now days! There are many facets of the trade,and knowledge in many areas is needed. These mail order classes just cost money,and are so,so at best. I would first figure out what you want to do the most.If working with wood is your interest ,then you have to learn inletting and its purposes,wood finishing,checkering. These all tie into a big package in it self. I would start out with the stock part of it and buy some good books on the subject. For a good general book on gunsmithing and has a lot of info,is Gunsmithing by Roy f.Dunlap. Hope i helped some,if you have any more ? just contact me. vangunsmith

Heres a link I found today looking for .300 Whisper info. Its about home gunsmith rebarreling

http://www.switchbarrel.com/default.html