I generally make roads 3/4″ or 1″ wide, which although not really “to scale,” makes them navigable by units on a 5/8″ wide base. Beyond that, I prefer to make my bases little town and village built-up-areas. A main road, with buildings clustered near it, and wide back yards delineated by a line of glue and some coarse turf as hedges. A 4″ hex makes a very convincing village. I’m by no means super skilled in this area, though – I’d look at Mike’s work and just scale it down somewhat.