Yeah, I think the two of you will do well and have lots of fun!
You will be well fed with DDP, so no worries on that side at all! I think you will have plenty of money to buy some gifts and enjoy some extra fun.
You might just try to budget the money over the course of the week and it will seem like you have plenty. My family tends to shop around visually at first and get a good idea of what we really-really want before we buy our Disney loot. We also will give each kid a certain budget for their purchases (and of course they can bring some additional $$ too).
Hope that helps!
