Finishing a Weathered Platform

[Dan R-M]

After reading Jeff's post on his platform I'm inspired to solicit some opinions on platform finishing.
We've got a nicely-weathered platform out there (the "heavy duty tarp" has outlived its water-repelling lifetime) and my plan is to take a few days before setting up the new yurt to 1) sand the t&g reeaaaal good and 2) give it 3-4 coats of polyurethane.
What have people's experiences been with this kind of process? I just think it makes a lot more sense to get the nasty stuff on and cured before enclosing it. I'd do this over a stretch of nice days, of course.