Yes, you can finish it in one day. Enter the park as early as possible by buying your tickets online, which would grant you a 1-hour Early-Entry into The Wizarding World before the rest of the park opens to everyone else at that didn't elect to purchase their tickets online.
As for reasonably priced hotels, I'm not entirely sure. Although I imagine staying on property at 1 of the 2 available hotels would probably be one of the more convenient options. As you could park your car at the hotel and walk over to the Main Entry Plaza in little to no time, saving some money on the General Parking fees for the park, which is usually $18-$20 nowadays.
Best Saturdays to visit in April are 4-1-17 and 4-15-17, the park closes at 10pm on those days and opens at 9am, with Early-Entry into The Wizarding World at 8am if you purchase your tickets online. Visiting the park on those days would give you plenty of time to experience and finish all of the offerings of the park, with exception to the Waterworld stunt show which has been in rehab for the past few months. If I'm not mistaken, Sydney, a forum member here mentioned that it may be ready to go sometime in April. You'd definitely want to experience that show on your visit, one of a kind! Be sure to double check by calling guest services.
Lastly, be advised that aforementioned dates are during Spring Break, and as with most theme parks, crowds are expected to be quite large. Early-Entry and purchasing some Gate A passes might be necessary. Around this time last year the park had just opened The Wizarding World and experienced some surprise rains, so it's difficult to gauge how this year's Spring Break crowds will be as last year wasn't your stereotypical Spring Break weather.
Does anyone else have anything to add?