Some of my favorite Disneyland Resort things...
Food: Cafe Orleans (TS) for the pomme frites, seafood gratin, and gumbo. The beignets are also very good, but I generally get them at the Mint Julep window (nearby) because of the seasonal flavor that they tend to offer (Cafe Orleans sometimes has it, but not always). The Plaza Inn has amazing fried chicken (lunch and dinner) and I really like the desserts at Jolly Holiday (Raspberry Rose Macron, seasonal offerings). Over in DCA, the Cove Bar (which should be re-opened as the Lamplight Lounge by September) has amazing Lobster Nachos. It's also usually worth checking out Schmoozies to see what kind of seasonal snack they are offering.
Attractions: There are so many, but my favorites include Haunted Mansion/Haunted Mansion Holiday (it should be HMH by the time you get there in late-mid-September), Space (should be Ghost Galaxy when you go), PotC (they're changing the Red Head scene right now), IaSW (better facade, has some Disney characters, and some different scenes), Buzz Lightyear Astro Blaster (better than the MK version - blasters have more range of motion and you can email yourself the ride photo for free), RSR, and TSMM (pretty much the same as DHS).
Entertainment: This is a hard one to predict. Usually by September, some of the nighttime entertainment goes to a weekend only schedule. Historically, Fantasmic! and fireworks are only on Fri (when there is no MHP), Sat, and Sun. WoC was presented nightly. They haven't said whether PtN will continue beyond the end of Pixar Fest or not. F! has the same basic story as the one at DHS (Mickey's imagination and the Forces of Good and Evil), but the elements and effects are very different. DHS has a better seating arrangement, but I think DL has a better show (my favorite differences are the dragon and the Mark Twain).
Other Things: By the time you, HalloweenTime should have started. Last year, they expanded the decorations into DCA, so hopefully those will be back this year. They haven't said anything about the Mickey's Halloween Parties yet (usually mid-Summer is when the announcement is made), so that's something to keep an eye on. The party is a lot of fun...there are some similarities to
MNSSHP and some differences (and if the rumors of the party moving to DCA come to fruition, then there will be more changes made).