I've seen people wheel with stock 16 steelies. Just check em out on YouTube. Bigger tires will help out a lot for offroading. A leveling kit paired up to bigger tires will suffice.
It will all depend on ur budget, goals (mpg, drivability, what kjnd or roads, etc)
At the end of the day, a stock jk is very capable of taking u from point a to point b the hard way.
33s can fit ur stock steelies...I'm not sure if it will rub the links though without spacers (I had stock steelies and don't even know their dimensions). A correct backspaced wheel will fit without any issues.