This infographic from our friends at Thai Visa Advice explains the difference in the processes as outlined by Brandon. I totally agree with him stay well clear of Poiphet. The Laos borders are more user-friendly than those with Cambodia.
Some of the visa run companies won't take you if you've had a "volunteer" visa as there's no guarantee you won't be "interviewed" at length, and they don't want any delays. Make sure you let the company know that you have one these
. Maintain your own control over the monthly transfers. Take your eye off the ball for one moment and you can rest assured there will be a stuff-up, and sadly Thai immigration are very anal about the monthly transfers.
"should have no issues" being the key phrase. Without knowing her full situation it's not possible to be 100%. She can try of course, and if it works it's all good. Very often people live in different countries to that of their nationality