My 4 piggies cage is quite big to begin with (5 x 3 with 1 x 7 loft including 2 x 3 kitchen) - so floortime is only once a week - to allow me to clean out the cage.
The floortime pen is 8 x 5, and I think this is where one of the real reasons for floortime lies. The floortime space should be bigger than the cage space - therefore giving the pigs more freedom, and excercise, and room to explore a different environment. If I were to let my girls loose in the sitting room - where their cage is, they would do exactly as your pig is doing, and find the most awkward space to hide in/under - there are loads of them available!
I either make a pen of cable-tied grids, and line with groundsheet, papers, sheet and fleece, using different hideys etc - or let them roam in the bathroom, with towels laid on the floor.
Another essential of floortime, is that is must be easy and quick to set up and dismantle - so that it is done regularly (daily for pigs in small cages). If your floor pens extend your pigs' usual cage space, and you create an interesting and stimulating environment, then that is far more important than if you allow them free range of your sitting room (where they will just hide under the furniture).