I went searching for a potential venue for "Vacation on the Moon" and found this publication: Palooka. They accept "graphic stories" submissions and are eager to publish "underdog" artists -- that is, folks who may not yet be widely published. They are a new literary journal in the US, accepting a variety of creative work. They charge a nominal fee to review prose and poetry, but so far it is free to submit graphic stories and comics.
I didn't find too many publications or even on-line sites accepting comics submissions (I sort of already knew that!). The norm seems to be self-publishing, which I think is totally cool. I also recognize a real need for anthology zines and journals. Not ready to step up to the plate yet to spearhead one of those, but it is definitely something worth considering for the future.