I have a Plex player with a bunch of movies at home.
If I wanted to take it on the road and watch it offline on a 32-43" TV with HDMI connection, what device could I use?
I don't do apple so no airplay (if that's an option)
I would normally Cast to SmartTV but in RVs the stuff provided are usually non-smart TVs.
Could I use some sort of Roku and attach an external HDD or USB stick?

I'm hoping that onboard DVD player will have some brains and will accept external HDD thru USB connection or straight up USB stick.

Depending on the tv, some have a usb right on them that can play media. Be careful of the container and format though.

Nvidia Shield is probably the most powerful media player on the market, can play 4k, passthrough all forms of audio, etc. This would be better than a Roku due to the limited media playback.

Most current br players can lpay media through the usb port as well, but again, limited to more basic audio and video files and formats.

What would you normally Cast to TV with? Does that device have an HDMI out? If so, why not just use that?

I usually just bring a laptop/macbook for that exact reason.

Connect HDMI, run VLC, play movies from USB/HDD. VLC even has a remote that you can use on mobile devices which works fairly well.

I like the idea of using the Shield. I've been thinking about picking one up since Roku4K only does 5.1

Are there different generations of Shield I should be aware of?

Also, if memory serves right the largest one they sell is 500GB.
That's not going to be enough for all the movies and I'm too lazy to try to sort thru them to see what I might want to bring with me.
I can downconvert them since RV TVs are not high end anyways.
I imagine Shield does support external HDD thru USB, like this Seagate 2TB 1K9AP7-501 one that I have laying around?

Galaxy phones. I can get the USB to HDMI ports but didn't want to limit myself to placing phone out of reach for when we want to advance the movie, take a phone call or answer a text.
Now that I think about it, casting might be done thru WiFi, which the RV will not have.

might be really easy to just set up a quick network in RV with WiFi.

Are the movies downloaded to your phone? Or are you trying to stream them from your plex server to your phone, then cast to the tv?

You can use a separate usb drive.
You can use either Plex or Kodi for playback.

The Pro model does have a 500GB HD built in but that is also used for buffering, My brother has the regular version and had to add a separate thumb drive for Plex, if the Shield have a smaller capacity than the movie.

Casey; I have them on my NAS server. I'm going to transcode them to a smaller format that will fit on a 2-6 TB USB drive.