Hi,
I believe that if the DVD player can output PAL60 and the TV can handle that standard then NTSC films should be ok, from what I`ve seen myself and read in this forum.
I`m lucky enough to have a Hitachi TV that handles PAL, 50, 60 and NTSC so have no problems with R1 discs.
If there is a problem it normally manifests itself as jerky video and audio when watching a film.
Hope this has been of some help
Cheers
Chris