You will definitely save money paying out of pocket! Especially if you don't normally buy dessert with lunch and dinner every day (who does???).
A couple of tips for you...if you want to purchase a beverage at the parks, just share one large instead of buying two smalls. Ice water is always free if you don't want to pay for drinks.
If your daughter does want to get an adult meal instead of a kid's meal, a few items you may be able to share if her appetite isn't huge. And, in reverse, if YOUR appetite isn't very big one day, you can get a kid's meal at counter service locations. Some of the kid's options are a roasted chicken drumstick with carrots, grapes, and beverage (or sub a soda, cookie, fries, etc).
Don't forget there are a couple of very affordable table service locations as well such as The Plaza restaurant in MK. For a few dollars more than a CS location you can get better quality food and larger portions, possibly even big enough to split.
You may want to look into buying refillable mugs for your length of stay at your resort if you plan to each drink soda/lemonade/tea at your resort once per day or more. If you think you would drink one beverage every 3 days there, it may not be worth it...but if you relax at your resort and fill it 2 or more times per day, you would save money by purchasing the mugs. Maybe have a rule that you only drink water at the parks (free) and can have sodas at the resort with the mug. Or not.

I don't know what your beverage preferences/habits are.
Oh, also consider places like Via Napoli where they do allow sharing as long as you're not on the dining plan. Split an individual pizza ($19) and share a dessert ($9-$14) or just share a large pizza ($30). I haven't eaten there yet, but we ate at Yak & Yeti table service in AK and their portions were huge...definitely somewhere you could share if they have anything on the adult menu that appeals to your daughter.
Breakfast is the cheapest meal of the day generally, so consider doing a breakfast buffet, snack for lunch, and a counter service dinner. Or a larger counter service breakfast (like the breakfast platters, not just a muffin), mid-day snack, and early counter service dinner.
My husband and I found that we were less hungry at Disney than we would be at home. We had the regular dining plan (1 TS, 1 CS, 1S) and it was WAY too much. We used our snack credits for a light breakfast (muffin or yogurt parfait at the resort) and skipped most of the desserts and still felt like it was too much food. That was without snacking between meals.