Get a taxi from Tirana to Ohrid - should cost about 80 pounds. If you want to save the pennies, get a bus from Tirana to Elbasan (plenty available) and then get a cab onwards to Ohrid across the border.
Get another taxi from Ohrid to Skopje - should cost about 40 pounds.
The Albania - Macedonia border is not a problem. Complete trip should take about 6 hours - I doubt you'll do it much faster if you need to take 2 flights
The roads from Tirana to Elbasan and from the border to Skopje are fine. Haven't been on the road from Elbasan to the border for a while though.
Elbasan is a dump, but if you can spare an hour or 2, definitely worth stopping at Ohrid to have a look round the town and lake.