Northsouth
I'm not sure how much closer you expect a train station to be to a small GA airfield, I would say 3 miles is pretty close.
Again I'm not sure why you chose to contradict everything I said but looking at the Scotrail timetable I note that trains from Croy to Central Edinburgh are every half hour from 7am till 8pm. Journey time 40 mins.
I also note that the Croy -Edinburgh train stops at 3 stations on the way. The last time I was unfortunate enough to take a train from Edinburgh to Fife I seem to remember around 10 stops.
Whilst neither has any published approaches, although there is an unofficial one at CBN using their NDB and DME, anyone flying to CBN in poorish Wx can fly the EDI ILS to break cloud for CBN. Have done it many times with no problem from EDI ATC whatsoever. Mind you this is probably possible at Fife too.
If you are in a heavy a/c CBN is around 150m longer. I go there in either an Arrow or Baron. With a few mates on board, with luggage, especially in summer I find that extra length reasuring.
I and several friends of mine regularly visit Edinburgh. Having weighed all the options up we opt to use Cumbernauld for all the above reasons.
I hope this satisfies you Northsouth. You seem terribly offended by my advice which was offered in the spirit of goodwill, and backed with a fair amount of flying up here. Your statement about Fife being the best option is very closed, perhaps you have shares there!!