Not quite...

... because O scale is 1/48 while HO is 1/87, so halving the O scale plan would end with a 1/96 version. Track separations will be messed up. Jose.

Potential problems

Clearances between tracks.

Any aisles and access openings might be too tight.

Humans

 Humans don't scale.  Aisle and access need to be accounted for.

Vertical clearances are different.

Great replies. Not quite and

Great replies. Not quite and a few tweaks seem to be the catch phrases. Let the planning begin. Thanks fellows.

"Logic tells me that a track

 As has been noted you might not get wide enough aisle spaces when shrinking a layout. The way to increase or decrease a layout plan to a different scale is to multiply the dimensions by the existing scale factor then divide the answer by the new scale factor. So an HO layout 8 feet long would be 8 X 87= 696 prototype feet divided by 160= 4.35 feet in N scale.  or working in inches 96 X 87=8,352 prototype inches divided by 160=52.20 inches in N scale.  4.35 '=52.20" we hope :> ).......DaveB

conversion in my mind

This will be a loose copy of an On3 which has usually no more than 3 tracks on a 24" around the wall. I will be able to have the same 24" but with HOn3​ my track spacing will be more open. Most of my condensing will be in the linear runs which will scale down just fine. Since I intend more of a concept copy I have a lot of freedom in interpretation and don't need to do a literal copy of the track plan. This conversation has really helped me. Thanks Blayne