The biggest "am I missing anything" question is what is most important to you--luxury? The so-called "Disney bubble?" Proximity to the main gates?
$3500 is about what we just spent for a 4 days/5 nights off-site without a thought about spending budget; it is near what we spent last week. More commonly, we plan $1000 for the first person in the group, $750 for the second, and $500 for anyone beyond that, for a 3-4 day trip.
If you are looking for keeping the Disney bubble or some luxury, then staying on-site is a good idea, either at Grand Californian or
Disneyland Hotel. Paradise Pier means you will actually be crossing a fairly busy street. All 3 hotels will take you through Downtown Disneyland if you are counting closest point to front gates. You get early access to the parks (one hour early each day, alternating parks), the ability to send your packages to your room, "Disney bubble" continuation, and a few other minor treats.
If you are more interested in staying as close as possible, or any thoughts about budgeting, then you might want to consider off-site motels. For instance, Best Western Park Place Inn and Park Vue are both closer to the main gates than any Disney-owned hotel. Sure, there's no Mickey soaps, and the shampoo bottles don't have mouse ears, but the are both reasonably nice, very comfortable, and very close. Did I mention closer to the main gates?

Clearly, we see where my priority lies! Bonus points: they are about 50% of the cost. When you are talking about a $400 room at Paradise Pier, or $170 for Park Vue, that $200+ difference would be 40 churros, 28 dole whip floats, a 3-person Main Street Electrical Parade dining experience at Blue Bayou, or an extra night at the hotel EACH DAY. I mean, after 2 days at an off-site hotel, you would have the price difference to add another day to your trip!
For airports, we prefer LGB, SNA, and then LAX, in that order. LGB is tiny, only has like 4 airlines, but is easily navigated, and close to the parks. $45 for a taxi to the resort area. SNA is a little larger, but still relatively small, equally close, and same price for a taxi. LAX is large, and while easy to navigate (great signage!), the transportation costs and time are twice as much as SNA or LGB. The airfare savings quickly dissipate when you add in additional time and cost. We've spent more than 2 hours from plane touchdown to front door of our hotel on a Sunday afternoon in July when flying into LAX. Just not worth it for us!