DIYbanter - Stretching a carpet in double-wide

Our double-wide, used as a cabin is now three years old and the cheezy
carpet is ocean-like with waves. I looked around and soon realized taht the
carpet was laid as a whole, half-house piece so the stud walls sit directly
on the carpet. So, I don't have nailing strips at those walls. I
understand that the carpet will have to be cut at these walls and nailing
strips inserted. But twhat the heck do I do with the holes cut in it around
those darn air vents in the middle of the floor. I can just imagine that
stretching will move the cut out into the middle of the floor. So, how
about this; I make the wall cuts, stretch and attach to the new nailers.
The part of the carpet which gets stretched into the vent opening gets cut
off and trasferred to where the vacancy for the vent becomes visible and
glue it down. The prime issue I see here is that the rest of the carpet is
*not* glued down. So, am I on the right track or not? I've never done this
and could use a bit of insite.
As always, TIA,
Chuck