In Scotland, for some the reaction was to participate in the war on either side.

Hugh Mercer, Wikipedia, for example, was a surgeon for the Jacobite army, and was present at the Battle of Culloden. After fleeing Scotland, he joined the British Army's ranks during the Seven Years War and served alongside George Washington. Later, he became brigadier-general in the Continental Army, defending forts and dying in battle. There are several counties in the US named after him. (Fun fact, the songwriter/founder of Capitol Records Johnny Mercer is one of his descendants.)

However, there were also many Highland Scots who sided with the crown. After Culloden, the ferocity of the king's army was definitely fresh in their minds. It is of course hard to speak in generalities, but many thought that another revolution against the English would be a futile undertaking.

Here is an eKeltoi article about that. I think this article focuses on the "average person" reaction that you were looking for. The author argues that many of the Scots who stayed in Scotland or went to fight for the crown did so to regain a stable relationship with England.

Andrew MacKillop has recently argued against the hypothesis that Highland troops were exploited as a means of winning over erstwhile Jacobites, stating the fact that the “majority of Highland units actually went to families with little or no need to rehabilitate themselves” and pointing out additional reasons why other possible sources of fighting men were passed over. While this may be an accurate analysis of the view of the élite, Gaelic vernacular verse from all around the Gàidhealtachd states time and again that the Highland soldiers will atone for their association with Jacobitism by British military service.

It goes on to quote from Gaelic poetry to support that claim.

Tl;dr: I think it's safe to say that in Scotland, the "average person" reaction to the American Revolution was mixed, and did not neatly split down Highland/Lowland lines or pro/anti-Jacobite uprising.