Under "Links" in the menu on this site you can find adresses for user made maps of the main arena, fields and industries. I personal use Glar's maps.
As for bombing tips, Eskimo made some good advice in this thread
http://bbs.hitechcreations.com/smf/Smileys/default/Forum2/HTML/000371.html ,but to answer you questions short neither HQ or fuel needs to be bombed to capture field.
Minimum is to just take out all Anti-Air guns and then bring in troops (ten), but this can easily be prevented by a single defender upping in a M16 for instance, as the troops are being released. Therefor it is also good to take out hangars (vehicle and fighter hangars and eventual the bomber hangar) to prevent such defence, and maybe the radar dish to make it harder for the defenders to organize well.
Bombing other targets (fuel, barracks etc) is mostly just a way to stop their offensive power, as fighters don't need troops and only little fuel for close defence of the base.
In the "help" at this site you can find a more thorough explaination of the strat of the game.
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Snefens
-=Aces High Training Corps=-