Re: float test?????
Welcome to iboats.
I think you are worried about the wrong thing, I would concentrate on the engine first since without an engine the boat is just a giant cork and sitting isn't real good on an engine.
If he winterized it before putting it up you may not have much to do if not you would have to at least clean the carbs.
Get a pair of muffs and some fresh gas and see if it will start and flow water, don't go above 1500 rpm with no load on the engine and I would spin the engine by hand for a minute or 2 just to be sure it spins okay.
As to the tubes not alot can happen to them sitting in a drive way but Biffle got it right, have someone drive it forward a few feet and stop fast then you put your ear on the tubes and listen, if there is water you will hear it.
The deck you just need to walk on, you will feel any bad spots.
Also, what are we talking about here, boat brand year and engine?