"When we go out, we’d better take [the] subway, [the] bus and so on." * There are some special cases where the definite article "the" should be used. An example would be when referring to official systems. A subway is a system of various infrastructure such as stations, rail tracks, trains and so on. (Reference URL: https://learnenglish.britishcouncil.org/en/english-grammar/definite-article / Look under the subtitle "to refer to a system or service". * There is nothing wrong with using "had better" though it would be good to know that it is used as a strong advice for someone in order to avoid an unpleasant outcome. If this is your intention, then using "had better" is fine. Otherwise, you can also use "can" to express the available choices without the element of warning. I hope this helps.

Yes. It's acceptable.