I have riden home from Balerno a few times and this is the way I usually take:
https://goo.gl/maps/nxqJwxb9bMN2
Past HW and down to Dalton Scrap, hang left, and out to Ratho. Over THAT hill to Newbridge and down to A8 (West bound carrageway) to foot bridge. Over the A8. Then along A8 (east bound) WEST on path to Lochend Rd and at Bridge up path to disused rail line to Kirky. The off at Kirky and on new path 9on left) to S Queensferry. Turn right at Shell garage and onto bridge via path on the EAST SIDE as the west side of the Bridge is closed weekdays. At North of FRB CONTINUE on pavement down to park n ride at Ferrytoll. Then under Railway viaduct and up into Inverkeithing. Thru InverK and out to Doubel roundabout. Right and then left and out to Route 1 turning on left by SNP cottage. Warning approaching cardiack arrest! Up this hill and into Dulloch proper. Following route 1 still get onto pavement at Hospital (Lynbank) and then at Holiday Inn, right into conf centre behind Holiday Inn.
The path from Newbridge to Kirky can be muddy but its been dry of late so just don't take your 23mm racing bike eh! The path on the north side of FRB behind the Queensferry Hotel is no longer great/viable due to the New Queensferry Crossing earthworks on the north side approaching Admiralty/Ferry Toll, so just stay on the pavement (shared use) past the layby to Ferry Toll PnR. North of InverK if you want at avoid the killer hill over the M90, don't continue up the B981 as it has blind corners at the top, instead head for either:
Pitreavie.
https://goo.gl/maps/giHzDsdLSk52
This has a large roundabout to navigate with fast traffic but you can stay on the path at the end of the motorway. I'd personally use:
Clocklunie road via Hillend:
https://goo.gl/maps/RYGGDoGgf9Q2
Clocklunie road has a cycle path up the whole length and brings you out at the Dogs Home (small white cottage at the top) where you cross the road and cont round the corner to B981 before crossing B981 onto Aberdour Road, where their is a cycle path on the right hand side path. You can go down Sandpiper Drive to Dunlin Dr or chose to cont down to pick up Route1 again at the 4th roundabout or just cycle up past Tesco HypermegaHUGEmarket along Greenshank Dr.
On the return do the opposite of your ride out, from the bottom of the hill out of InverK high st and at the Bridge on Ferryhill Rd take the pavement under the viaduct. stay on the east side of the FRB and the East side of the Bridge is two way cycle traffic.
What time you finished? Hillend Tav is nice for a pint on the way hame!