Well, well, this is a pretty open ended question. Are you asking where you should purchase your firearms, where you should shoot them, or a little of how you should start your collection? To start your collection, it doesn't really matter what you start with, just make sure it's in good shootable condition. If you plan on shooting them often, i'd probably skip the Enfield first since .303 British is a rather rarer and more expensive round. Both the Nosin and the K98 both have fairly common ammo available at cheap surplus prices. However, if you plan on just buying 'em for the collection sake, to say you own them...start with the one you want the most. Or whichever you can find in best shape for the price.
For shooting them, yes.. middle of the desert is fine. As long as it is 500ft from the nearest residence and you arn't aiming towards a busy location (i.e. a highway, or shopping complex). It is also better to shoot in "bowl" or valley. Where the bullet will just go into the ground if you miss.
For buying the rifles, I really am unfimiliar about west coast gun regulations [so, some changes may apply for above], however you can legally buy firearm (legal fireams) from other private dealers with no permit as long as you are from the same state. I would recommend this option for right now. A good way of buying guns is also from pawn shops and places like that, where the might require a hunting license, and background check, not always necessary a pistol permit. Some states are more lienent than other with arms sales and regulations so I would advise checking this out for a more specific answer.
