For Ana, more Scottish festivals which have a strong trad element, if not exclusively traditional:
Girvan (early May in S Ayrshire) - as mentioned by Fred: I go every year and can recommend it.
Keith ( mid-June, between Aberdenn and Inverness)
Stonehaven (2nd weekend of July, on the coast 15 miles S of Aberdeen)
Innerleithen (3rd weekend of August - Scottish Borders between Peebles and Galashiels - overlaps start of Whitby)
Kirriemuir (1st weekend of September - in Angus, a bit NW of Dundee)