The Embassy Suites Jamaican Court has packages for Universal and Sea World (or at least they did have in the past). The room worked out to be about $99 a night (I know, not exactly midrange, but...). They have (or did have) free shuttles to both parks (parking is $7 a day). The main cost cutter there would be the breakfasts. If you haven't stayed there, you'll find them hard to believe - an all-you-can-eat hot breakfast buffet plus you can have anything else you want cooked to order (all included in the room rate). Their rooms are 2 room suites which would give you plenty of room and include a microwave and fridge. We ate a big breakfast, a late lunch, and snacked for dinner. The I-Ride Trolley goes up and down International Drive for about $1 a day (which would provide ample dinner options if you don't have a car), but I'm assuming you will be driving.
We stayed at the Convention Center location, but they sound very much alike. The Conv. Ctr. property had an indoor pool (you never know in March), and I think the JC location does too, but you'd have to check to be sure.
Good luck with your trip!