Apparently, you have access to the internet, so look at the variety of guns listed at
[url]
www.trackofthewolf.com[/url]
Auction Arms or any other gun selling links will give you a free look at various guns.
Break gun types out by as you stated flint or percussion. Also see matchlock, dog lock, wheel lock and handgonne for more variety.
Half stock or fullstock are big categories.
Rifle or smoothbore.
There are numerous books. What types of guns interest you or what area or time period interest you?
A Hawken can be seen though a web search.
[url]
http://www.thehawkenshop.com/[/url]
A T/C Hawken can be seen at
[url] www.tcarms.com[/url] This bears no resemblance to a real Hawken, but is a common (I have several) intro gun. The Seneca and Cherokee are guns that were put out by T/C and are well made smallbore halfstock rifles that are no longer produced due to a fire in the factory. They were made along the lines of an Ohio halfstock.
As to learning about the Pennsylvania rifle, try Kindig's Thought on the Kentucky Rifle in Its Golden Age, Dillin's The Kentucky Rifle or other such publications which you can see at better libraries.
Dixie Gun Works and Track of the Wolf catalogs are helpful, but dangerous as you will be lured into the purchase of vast quantities of parts to build more exotic gun projects and you might even complete some of them and use them to kill animals or win rifle matches!
Be ware!!!
CS