I own a Swimming Pool cleaning and repair service. Quickbooks was loaded on a laptop at my home office while my business partner didn't have direct access. After signing up with Method, my business partner can easily access quick books data. She can add/edit customer information, customer jobs, complete work orders, create invoices, receive payments, generate various reports. If I happen to have Quickbooks open on my laptop, I can literally see customer updates instantly. For example, if I'm looking at a customer phone number and my partner changes it by accessing it through Method, I will see it instantly change before my eyes. While Quickbooks is running, Method will constantly look for updates and sync them accordingly.
Based on how you described your needs....Method is perfect for you.
I do come from an IT background so I have been customizing Method to suit my needs better; however, I think it would accomplish what you desire the second it has been synced with your Quickbooks.
It's not that expensive to give it a try.
Good Luck,
James