I tried HO track, modelling 2' gauge sugar cane lines, before I came to G. Looked much too small in the garden and impossible to keep trains on track with any leaves/twigs etc. Only laid a few metres of track before I saw the G light.
I've sometimes wondered if I could do HO on a raised baseboard (like I have for my G) with a fold down lid to keep the muck off. Might be a possibility for those with no room inside.