What I can answer is we spent 1 day (started late) and were able to get most of one Universal Studios park with fast passes. I would recommend at least a full day per park. I would also recommend paying the extra 10$ for prime parking, after walking all day it was nice to be closer.
For visit whole park Disney took me 4 days... The cheapest right on March April also Oct to go.. Wallet be ready.. parks open at 9 am to 6 pm on certain days prime parking is 35 dollars and for Universal studios cost us 149. Dollars on weekdays weekend a bit more
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