I remember seeing this movie ONCE when I was in elementary school, and TODAY I finally tracked it down.
I thought I had dreamed this scene because I had only seen it that one time, but alas I have found it...

http://www.tcm.com/mediaroom/video/432230/Long-Long-Trailer-The-Movie-Clip-In-The-Wilderness.html

Is this the only time Lucy wallowed in the mud?
My only complaint is I wish it was longer! Perhaps she could of pushed Ricky in!

Huh. Not sure if this will make you feel better or worse, but your long-lost scene has been on one of Mark's WAMTEC tapes for... 15 years? Maybe more? I had it on one of his VHS cliptapes... My only recollection was, "Huh. That's Lucy from I Love Lucy. Getting muddy."

There's another messy scene in that movie. Lucy is trying to make dinner while on the road. Ricky is in the car, happily driving over rough terrain while Lucy is in the trailer making an unholy mess. It excited me when I was younger, but I'm pretty sure it was just flour and stuff.

-PYP

I saw a preview of that film. It went on forever.

Sorry. I will get my coat.

Please note the gags in my upcoming scenes will likely be worse

Because it was a long, long trailer?

Norman

Thanks Goodwrench! I posted the YouTube version a couple months ago, but yours is much better quality The other messy scene is also linked to in that post along with some very nicely looped GIFs I found on Tumblr: http://umd.net/forums/i-love-lucy-chocolate-factory#454340. Still no sign of the colorized chocolate factory scene

Thanks Norman!!!!