I have a friend coming back to Thailand (from Australia) after she was here approx. 5 weeks ago. She has a TR Tourist Visa that is stamped "Good for TWO journeys", does this mean that she can enter Thailand again on that same visa?

Yes she can obtain another 60 day entry by leaving and re-entering the country. She must do it before the enter before date on the visa sticker,

She can also obtain a 30 day extension of stay at immigration that would give her a total of 90 days without leaving the country.

Thanks for your response, that solves her problem.