LOL, you really don't know anything about QB do you?  You can host on the fastest server in the world with a TB fiber internet connection and it does not matter.  The desktop app downloads a TON of data locally and the performance is limited by the slowest factor.  In this case it would be the wifi connection of the sales rep in the field.  This is why we desperate need a thin client to run as an app, on a phone or tablet.