March is considered to be "peak" season in WDW. If you got ASMo for $89/night, you've already gotten a discount over the rack rate of $109/night! WTG!
Personally, I like Chef Mickey's for breakfast over the Crystal Palace but that's more due to my preference for the types of characters (Mickey & Friends vs Pooh & Pals). To save some money, you might want to consider joining
Hotwire Savings Club and ordering a few vouchers. The breakfast vouchers cost $18.25 per adult with no charge for shipping. It will cover the cost of the buffet ($17.99) plus tax (6.5%) and gratuity ($15%). So, instead of spending $21.85/adult for the meal, you'll only spend $18.25. Child vouchers cost $11.00 and will save you about $1. for each character breakfast.
If you like eating a sitdown meal at least once per day, consider making that meal a sitdown lunch instead of dinner. Lunch menus often have similar selections to the dinner menus but with smaller portions and lower prices. I like using the Vaction Kingdom Lunch Vouchers for these meals but even if you don't like the idea of using vouchers, you'll save money over eating sitdown dinners just by switching up your dining schedule.
Another suggestion that I got from MouseSavers.com was to get the Trails End Buffeteria (Fort Wilderness) as take-out. The cost is $16.99 for an adult and they give you one large styrofoam container, a salad container, a soup container and a beverage container. Load them up at the buffet and take them home to share.
Do the AK "meals plus" program and get a counterservice meal, small beverage, voucher for popcorn or ice cream and a voucher for bottled water for the price of $11.99/adult.
In EPCOT, one of the best-kept secrets is the Tangierine Café in Morrocco. The Shawarma Platters include hummus, tabbouleh and tangierine couscous salad, Moroccan bread and chicken for $8.95. It's more than enough for one person and if you add another sidedish for $1.95, it can fill two people up easily.
If you have a car, try going offsite to eat. You'll have your pick of many family-friemdly, affordable places. I'm sure that you'll get plenty of suggestions. Have fun planning your "budget" trip!