First, a disclaimer, I used to work for a company owned by the mouse, but did NOT work at the parks

RE Big parking at Disneyland - the WHOLE operation at Disneyland would fit inside the main parking lot at Disneyworld - so that should give you an idea of the size diferences

Disboards.com (in this case, no entanglements except as a member) seems to have the best tricks and tips

One big one at DW - the water there really stinks. There are water bottles with carbon filters available - they made the water fine - well worth the few bucks

"Off season" and "Peak season" times are that way for a reason - usually "Peak" is when schools are out - when schools are IN, prices, lines, etc go way way down. Pick a really odd time (like labor day week), when school is back in in most of the country, and the weather is still HOT can be cheap, and you can have NO lines, BUT - it's HOT!! We'd do the early AM, head back to the hotel and swim in the afternoon, and then go back to the park

IF it's in budget (BIG if - they are NOT cheap), staying at one of the Disney resorts - particularly on the higher end, can be totally amazing, particularly if you to the "go back to the room" thing, and get to experience some of the activities AT the resort

They are VERY good at seperating you from your Money, and at the same time making you say "gee, I'm having fun, I'd love to come back"