Helensburgh is well-served with restaurants to suit all tastes and all budgets. This does, however, attract visitors from the surrounding area and advance booking is recommended particularly at weekends. See more about the area here.
The town is both a seaside resort and also a dormitory town for commuters to Glasgow. There is a range of accommodation available, not all within the town itself. Popular websites like TripAdvisor.co.uk , Booking.com and LoveLochLomond.com provide up-to-date listings BUT be aware that their search algorithms don't always take account of the Clyde Estuary! Towns like Gourock and Largs aren't too far as the seagull flies, but are considerably further away by road. Also try Helensburgh Local Tourist Information on Facebook.
Space can be made available adjacent to the clubhouse for limited numbers of tents and campervans, but requests must be lodged via the Club Office so that adequate pre-planning can be arranged. FIRST COME FIRST SERVED as the space is not unlimited.