To get the most from Scotland, and to at least give you the chance to get some mileage in, regardless of the ski centres running, you really need to consider getting off piste. This would entail split board, or maybe considering snow shoes in addition to your board. (Don’t ask me which works best as I’m a skier.)
To keep safe you will need some mountaineering knowledge and a good understanding of snow conditions. The latter might seem a bit dry but the weird thing is, the more you look into it, the more interesting it becomes.
This will open up the opportunity of using any ribbon of snow, anywhere, anytime. Think early season, even ski fencing, or later runs down burn lines (terrain traps, but very exciting, especially in spring when holes start appearing ;)).
Have fun and stay safe.