I think the most important thing to keep in mind, if you want to avoid buying a lot of gear, is that your bike is probably already set to go, and you're mostly expending effort solving problems that you may or may not have.

There's always going to be ideas of what changes would make it a more ideal touring bike. But until you know what problems you're encountering, I wouldn't spend much time worrying about the problems that everyone else has solved.

Best of luck.