Anstruther to Dunnottar

You would need to catch a bus to Dundee and then train to Stonehaven and then walk or taxi to Dunnottar. You are looking at about 3 hours one way...

Remember the castle can get closed in bad weather, particularly if there are very strong winds.

Wasleys is pretty good with her buses, but the X7 from Dundee to Aberdeen stops at Dunnottar. You also have another change onto the 99 at St Andrews
I would get the X60 from Anstruther- direct to St Andrews in half the time of the 95.

Whichever way you do it is there hours and a bit by bus.

A Stagecoach East Scotland Day Rider for £11.50 currently is what you want. Single Fares cost £11.55 each way currently. Normally the X7's are double deckers with on board toilets but don't rely on it.

You could get off the 99 at Leuchars and train to Stonehaven in 1 hour 10 minutes then bus, walk along the cliffs or taxi back to Dunnottar. That should be about an hour faster overall.

Booked ahead of time an Advance train specific fare is £9.30 each way, plus your day bus ticket as above for Anstruther to Leuchars return and maybe the local bus Stonehaven to Dunnottar

Thank you both, researching trip possibilities continue.