If you're planning a move in a relatively short time (and I'd consider 5 years short given how long it takes me to build a layout) I'd consider a smaller switching layout. This will provide a few benefits:
- Can be accomplished using just snap track/predefined track sizes (Atlas code 100 or 83 if doing HO)
- Can be small enough to finish in relatively short order so you can get to using the layout - I'd recommend something in the range of 1.5'x4' to 2'x4', or thereabouts. Will get you to operations faster and you can work on details while mixing in operation sessions
- Gives an opportunity for a "quick win" - starting too big can be overwhelming and lead to not completing the layout
- Practice for a larger layout - learn how to wire, scenery, etc.
- Can be incorporated into a larger layout at a later date
- Easy to move, may not require disassembly
One example of this can be found here:
http://www.wymann.info/ShuntingPuzzles/Timesaver/timesaver-trackplan.html, but there are plenty of examples of smaller switching layouts on the web.