Cross Post- trail riding in Scotland

My sisters and I are planning a trip to Scotland next summer, and would like to include 3-4 days of trail riding in the Highlands. Does anyone have suggestions as to good outfits? It’s hard to know from a web site! We are 2 strong intermediate riders and one somewhat rusty. From reading, I think they describe Pony Trekking as a walk on a horse, whereas a trail ride is more challenging.
We’ve done Ireland in the past, OK with unpredictable weather!
Anyone ridden in Scotland?