Yes. The free DVD FAB DECRYPTER will decrypt and remove copy-protections, and leave a perfect copy of a DVD on a hard-drive.
Then, browse to those resulting DVD-FileSets and, in the VIDEO_TS subfolder, right-click on the VIDEO_TS.IFO file and "open with" your DVD Player's software. (This is "creating a File Association" - one type of file is 'always' opened by one certain software package.)
Once that's done, double click on that same VIDEO_TS.IFO file and that DVD will start playing, as if the disk was playing. Menus, alternative subtitles, language tracks, etc. - all will be available.
I don't often play videos from External Drives but rather I'll copy a batch of those to my local drive and play those, then delete them and copy another batch of DVD-Files. Over and over.
You can put a few on your External and try playing them, yourself, and see how the play-back appears. If it's satisfactory, then you have a good idea of what the notebook's playback will be like. If there are stutters, pauses or apparent "buffering" issues, then the files can be transferred to the local hard-drive for smoother playback. If needed.