First off congrats on the first visit you'll have to let us know how you find everything here in Florida!
IMO Universal does need two full days as you can do most if not all by 6/7 if your taking your time and starting at like 10ish...
I tend to take a small break at like 2 and go back and eat at the hotel, and relax for a couple of hours...it really makes a big difference in the tiredness factor in it all, of course last time we went full bore and did 3 parks or at least all the major attractions in one day. That I think was too much for our style of exploration, but the way we usually do it we find we are better off as everyone's kids are screaming and they seem ready to leave by the time we get back to the parks to use the rest of the day.
For a meal that's really good for under 50$ a person I recommend Raglan Road, VERY good food at downtown Disney, they also got some fancier options for the food explorers in your group.
Have fun! Enjoy yourself its a very different experience from Cali and in some ways I think better.