Both games are naturally 4:3 aspect ratio. So when I try to play them on my 16:9 screen, the top & bottom of the game screen is not visible. For LotR I can Alt-Enter since it's running in a DosBox window which isn't ideal since then it's tiny, but at least I can see it all. For LotR II, Alt-Enter doesn't do anything.

Is there a way to get these games playable on a widescreen?

My monitor has an image size selection where I am given the option of auto or wide for games. Wide gives me a similar effect on LOTR2 as you described. Also if you're running Nvidia hardware in the Forceware control panel there's an "Adjust Desktop Size and Position" tab. On the most recent drivers I set scaling mode to "Aspect Ratio" and "Perform scaling on GPU". That fixes it for me. For some odd reason allowing your monitor to handle scaling screws up these older games in my experience. Anyways I hope some of this helps and if not let me know. Regards