Waterford Lakes Towne Center is definitely the closest BB&B to UCF. It takes between 5 and 10 minutes to get to Waterford Lakes from the corner of Alafaya and University (the entrance to UCF), depending on traffic and stoplights. I don't recommend the Super Target for groceries, though -- unless things are on sale, you can buy them cheaper at other grocery stores nearby (there are Wal-Marts, Neighborhood Markets, Winn-Dixie, and Publix stores close to campus). Super Target is a great resource for anything else you could possibly need, though, and they are extremely well stocked with campus living items each August to accomodate returning UCF students.
My son (who is at UF, not UCF, but I imagine the situations are similar) does not have a meal plan and finds he eats better and more cheaply than he did when he had a meal plan last year. Dining hall food gets old fast. He keeps a decent fridge in his room and gets groceries weekly so he can eat on his own, plus he orders pizza with his roomates (which ends up costing a lot less than dining hall food) and hits Subway fairly often. We are paying quite a bit less for food this year than we did when he had a meal plan.
Also, the UCF Lynx bus used to go right by Waterford Lakes on a regular basis -- however, you should check directly with Lynx to make sure, because they have cut some routes due to budget issues.