I have a friend who lives in Ratho, and it so happens that she commented on Facebook yesterday that she thinks she's going to have to start driving to work rather than take the bus, although she'd rather take the bus, because now she has to go to Leith the bus takes twice as long as the car does.
(I think she said it is 20 miles each way, so cycling isn't an option.)
It's only a little over ten miles from Leith to Ratho by bike? (She might not live and work at the two points I clicked on though).
You can ride along the canal to NEPN and thus to Leith. Less than a mile on road. With a folding bike it would be possible to short circuit whichever half is slower (i.e. bus from Ratho into town then ride down NEPN or vice-versa?)
You could even just drive to the park and ride and take the canal from there, amongst other options...