I built Phase 1 of my layout, a 5x12 foot free-standing table, in HO, as a single piece. Because of the way the house is layed out, and the easily-removeable-if-necessary legs, I could get this section out of the house without a lot of trouble if I had to. However, it would be quite a headache to get it into any other part of the house.
For Phase 2, which is a 19 foot by 2 1/2 foot run along a wall, with a balloon at one end for a loop, I took a more modular approach for the benchwork. I built this in 3 sections. I used barrier strips for the track power bus and the lighting bus for structures and street lights. Mostly, I tried to put rail joiners where the tracks crossed between sections as well.
But, this is not designed to be “portable” or easily moved. Instead, it is built so that it could be dismantled and moved without too much damage. So, all of the wiring for turnout control, for example, runs straight from the turnouts to the control panel. Scenery will run right over the joints, and will need to be cut if the sections must be separated, although the thin layer of plaster cloth and Gypsolite shouldn’t present much of a challenge there.
I am building Phase 2 as a single entity, as if it were one piece. The mainline trackwork is all in place, although it’s not all glued down yet, and only a small section is ballasted.
I have already secured the rights to the real estate, though. I’m not sure about how much more I can acquire, but this section should keep me busy for 2 or 3 more years, at least. At that time, though, I will be at least considering retirement, and our daughter will have finished her undergraduate schooling. Possession of the train room will be important, in case she comes back to live at home for a while, and the train room reverts to her “family room” again, the way it used to be.