That sounds like an exciting trip! I would think $10,000 would be plenty, but I guess you have to add it all up to be sure.
A few things:
Disneyland only has passes up to 5 days, so if you want 6 days you would need to buy an extra ticket for that.
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Undercover Tourist and Getaway Today are two reputable websites that sell Disneyland tickets. They have sales once in a while that can help with ticket prices. Also as you know since you are a WDW vet you can get non hoppers, or not add
Genie+ to save money. (I always do hoppers, but skipping them can be a good way to save money.)
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You've probably heard this, but hopping is SO easy at DL because the parks are right across the esplenade from each other, and Downtown Disney is right there too. It's all super walkable.
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The resort hotels really vary in price.
Pixar Place (Formerly Paradise Pier) can be as low as $400-500, Disneyland $500-600 ish Grand Californian can be more like $800-900 depending on the room. Suites or club level will cost more. The prices depend on days of the week, time of year etc. There are usually spring sales.
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There are tons of great hotels within walking distance, some even closer than the resort hotels. Be sure to check hotels that aren't considered "Good Neighbor," too. You can get a nice hotel for around $300 right across the street from the Disneyland entrance, less than a 5 minute walk. (Some of the fancier hotels across the street can be up to $500 or $600 depending on the room type.)
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When flying to Disneyland you have a number of options for airports, and can get much better fares depending on which you choose. Also depending on your airline, I guess.
Times are estimates, it depends on time of day etc.
SNA (Santa Ana/John Wayne) 15/30 minutes away
LGB (Long Beach) 30 minutes
LAX 45-90 minutes depending on traffic
Ontario 45-60 minutes
Burbank 60-90 minutes