Three Hole Dog Box Removal Question......

I am considering buying a mountain top 3 hole slide in box with the two full bottom drawers and front closet. It weights 650 pounds. My issue is that there will be times when I want to remove the box (non training months) or to save fuel mileage on long trips that arent dog related. Just wanted some opinions from those that have a system for removal?? I do not have access to a forklift. I will be using a chain hoist and will most likely build some sort of lift truss out of 6x6s anchored in concrete for the removal process...
How difficult has your experience been with removal, IE hoisting it out then getting it back in.
Also how much did box affect fuel economy..? In addition, it will not be bolted to the bed so what are other anchor options?

I was set on buying a 6 hole trailer but after reading some reviews about the dogs bouncing, dirt, exhaust etc I am pretty sure I want to keep the dogs on the truck for a better ride. Storing my gear in one place was my main objective and i can do this as well as easily access the gear due to the long drawer slides without having to get into truck.

In addition, I can get a better quality built product with the three hole for less money that I would have paid for a trailer built of lesser quality.

Just curious if anyone on here has done this??

Any pictures or set ups would be appreciated. Also the tech from mountain top suggested that I have them install lifting eyes on the box