Am having a similar dilemma myself after signing up to a road “holiday” in Belgium. Roadbike was my turbo trainer and the 11-25 cassette and standard double chainrings are filling me with fear (I don’t run a granny on my MTB but think that this combo on my roadbike will make me walk).
Will a compact be enough or should I go for a new cassette as well, I understand that at most I would only be able to go as high as 26 or maybe 28 at a push on the short cage at the rear.