One way to try this is with FAVC. No guarantees that it will work though, since this is outside its original purpose. FAVC is designed to convert various types of video files to dvd format, but PAL->NTSC conversion with it has been hit or miss, depending quite a lot on the input files I believe.
FAVC can make use of DGPulldown, which is why it can be used for this type of conversion.
FAVC is free to download and use. http://favcfavc.googlepages.com/ Make sure to install AviSynth and Net 2.0 if you need them (they are free and there are links to both at the FAVC site).
Starting with .vob files, I think I might use Vob2Mpg first, to remove the video from the .vob container files, then import the resulting mpeg2 file into FAVC. FAVC does have official support for .vob files, so this isn’t necessary, just my preference. http://www.videohelp.com/tools/VOB2MPG Vob2Mpg won’t degrade the video, it just takes it out of the .vob files.
Once in FAVC all you have to do is choose the HC encoder and make sure the output files are set to NTSC setting. You can make a menu in FAVC also, and it is possible to set it to burn automatically to a disk using ImgBurn.