Hope you don't mind if someone from the States is on your board but I see I can answer a few questions you have. And feel free to ask me anything.
Friendly and Denny's for two adults will cost about $12 - $15 total. Friendlys is cheaper.
Here is another place you all might be interested in. Sweet Tomatoes has a very large salad bar, baked potatoe bar, pizza, mac and cheese and a sundae bar & desserts. If you sign up to get their coupons emailed to you, they often have buy one get one coupons. For the two of us it cost us $12 total for dinner. They also have a coupon that 4 people can eat for $19.99 after 4 p.m.
http://www.sweettomatoes.com/
** Also wanted to mention that the nearest sweet tomotoes is located a mile from DTD. Take Hotel Plaza Blvd to the intersection of RT 535. at that traffic light you will go straight crossing over 535 and enter the Crossroads Plaza. Drive straight to the back and you will see if off to the left just behind TGIFridays