If Ulead will read MPG files, do your rips with DVDFab’s VOB Passthrough function, then just change the output file suffix from .VOB to .MPG in windows. If it will not read .mpg, try another editor. Some (e.g. AVS Video Remaker) will edit MPEG2 without decoding and then re-encoding and work much faster. I don’t edit much and have never used the Corel product that you have. Not sure about the freezing–I’ve never had that happen in DVD to Mobile.
//EDIT// I see the newest version of Ulead will do AVC (H.264) files. This would also be a good choice for maintaining quality and DVDFab has several profiles in DVD to Mobile that work well.