I think the only good reason to grow past happiness cap is if you plan to whip them away soon, or you are about to complete a happy building or hook up a luxury resource. If you are having trouble on noble, try this:
Early techs, get needed worker techs for the resource tiles you can improve, and get bronze working for whipping, chopping, and bronze (axemen). Then go straight to alphabet. Once you have alphabet, you can typically trade for most of the techs you skipped.
Chop wood to get your settlers out quicker, and to help build early buildings like granaries and libraries.
Find bronze and plant a city beside it. If you are close to another civ, you will want axes to go to war with them. If you aren't close to another civ, you will need axes for barbs.
Plant cities by rivers if possible, and make a lot of cottages and work them. One or two good food tiles plus a lot of cottages = lots of commerce, plus decent production from the whip.
One solid simple way to play on noble is to have 2 cities focus on production, and 2 cities focus on commerce through cottages. Do just this well while making sure you have enough military, and you should have a commanding lead over the AI by the time you have Code of Laws and can then think of expanding a little further.