Ashton,
You're off to a good start with the Hasegawa Longbow kit. Only the Japanese have the capability to carry Stingers on their Longbows, but the mounting lugs are present on the wingtips of all D models. As for the contents of avionics bays, a lot of that is somewhat sensitive. The Verlinden resin update for the AH-64A had some bay interiors, but they were fictional for the most part.
I will say that the decals in the kit are completely inaccurate for a US AH-64D, but fear not, I'm working with Twobobs on a new, comprehensive AH-64 decal sheet that should be out in a month or two. If you're looking to do a Block 2 AH-64D (2003 model year and later), there may be some resin coming out soon to update the Hasegawa kit. I'm working on the masters now.
If you need a copy of the Walkaround book, drop me an email.
Jon