Bruce,
Welcome to the Remote Forum.
A floating floor in a remote truck is important if you're building a real control room. The weight of the floor is another story...
Can the vehicle handle the extra weight? How much of the CRM height can you loose. Are you going to build the CRM walls off your floating floor? Many things to consider.
ASL's truck one (build back in 1987) has a floating floor. It's a framed parque floor floating on rubber pucks.
Not every mobile unit has a floating floor... How do you feel about it?
I split this thread into another thread called,
Questions about designing a mobile recording unit -- expanded
Your additional posts and my reply in there waiting for you...
Check it out!