I just found this thread and appreciate all the suggestions. Planning to be in London early April but want to spend weekend visiting friends in Scotland. Train sounds ideal. Suggestions are very helpful.

One more question, once in Scotland I am interested in getting to Berwickshire. Do trains run in Scotland to that location or other choices?

sanlass: Where in Berwickshire? It is a fairly large county. The trains basically hug the coast, if you need to get inland you'd need other forms of transport.