first line chemo checkup dilemma

my sister, who was diagnosed with UPSC IVB in February, 2011, is coming up on her third carbo/taxol treatment. Her oncologist tells her that she will get a CT scan as well as a CA125 test to see if the treatment is working. Unfortunately, the CA125 test does not seem to be a marker for her--she has been under 30, including when she had colon cancer. Additionally, she is not confident in the local specialists and their abilities. She saw a variety of specialists for over a year, had CT's, PET/CT's, MRI's, chest xrays and bloodwork and their diagnosis were all over the place. In fact her oncologist was amazed that nothing seemed to confirm and said that she never had a patient with so many false positives. After they finally took a biopsy of a suspected uterine tumor and it turned out positive, they performed a total hysterectomy. The gyn/onc was expecting a stage II endometrial and found cancer spread around the peritoneal cavity as well as a destroyed fallopian tube.
At any rate, bottom line, she went to MDA for a second opinion and is wondering if she should go back there for her ct scan following her third treatment. Is there really a significant difference in CT scans? Logistics and $$$ will make trip to MDA difficult, but if it's critical she/we will manage somehow. My thought is to have the follow up tests done locally, and if there are questionable results, go back to MDA. I do think, however, that she should go back to MDA after she finishes these six treatments.
Other than a decline in CA125 count and nothing showing up on the CT scan, are there any other ways to know that the chemo is working, or is it no news is good news?
Thank you all for sharing your knowledge about this horrible disease. Other than this and the inspire board, it's very hard to get a handle on it.