Trying to find a story that I read a couple years back -- Can't recall if it was an online short or something in print, though I'm fairly certain it wasn't more than novella length.
The protagonist built a linear accelerator based on a mountain top and extending into the air for miles (balloon lofted, I think) to launch cargo and eventually manned craft. Of course, they face the usual sabotage / espionage type issues, etc etc ..
Ring any bells?
I should note that it isn't Moon is a Harsh Mistress, since that does seem to be the top search result when I try to Google and the first answer I've received in here. I think the story was written more recently.
Started a bounty, maybe with the beta going public someone might be inspired to locate this - unfortunately my attempts to Google it have failed. It isn't a DD Harriman story, fairly certain it isn't a Heinlein at all -- I think Matthew Nichols is correct that this was an online-only publication from the past few years.