The Romans wished to fight a conventional war, as they would win.The situation is a "vietnam" scenario or Normans in Ireland Scenario, avoid the firepower/technology and try not to lose, by not losing (or appearing not to lose) keep your opponent moving from small brushfire to the next till they leave you alone out of sheer irritation, and a desire not to commit expensively trained troops/logistics backup to a marginal area with few obvious resource or taxation returns (vietnam fits the bill on technology if not political weight, Norman Ireland is a similar scenario in terms of potential pecuniary gain). When conventional battles were fought , Mons Graupius is the obvious choice , the Romans annihilated the Caledonii.
The other side of this though is that the next move was the division of Britania into "superior" and "inferior" provinces , the latter with a predominantly Auxiliary troop presence. You fight irregulars with your non-Roman auxiliary troops , getting fighting men away from their own home areas (Sarmatia and Batavia for example to Ribchester and The Wall (Hadrian's)) thus pacifying two areas at one stroke.
I mention Salway as an excellent source on this era in my blog on "Hadrian's Wall" -have a look , though a little dry the scholarship is razor sharp.
note: as far as Vietnam goes I wish to mention the book "Hell in a very Small Place" on Dien Bien Phu (Bernard Fall)-this is as regards the French campaign in Cochin China (as was).