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I'd start by looking at skyscanner or googleflights and deciding if you want to go direct or indirect. Indirect is usually cheaper, and look at flying to Tampa or Miami as well as Orlando. Ok, so you are allowed on to the Dibb for the Disney bit - there's a link to decent ticket sales sites, there's not often much difference in prices between the sites. Orlando offers a massive range of accommodation, hotel, motel or villa? Possibilities are endless.
I use ebookers/expedia to book hotels/motels, and flights & car hire, and if you sign up to quidco/topcashback or whoever, you can get cashback too.
Car hire can often be cheaper when booked with a flight, but check that car insurance is included, some companies offer cheap car hire but slap on massive insurance costs.
We've stayed on both coasts several times, prefer the Atlantic coast - West Palm Beach is great, Cearwater great also.
Stick with your plans, don't get blinded by Disney, although if you're going to Universal, it really is worth staying in one of the hotels that offer express passes to the parks (or whatever they're called). You can book the hotels with tesco vouchers on hotel.com.