Old Stagecoach Trail and Old Santa Susana Stage Road 

Got ur message/question.  I think you were encountering a situation where the NRHP name in our LA list was a red-link and was different than the name of a pre-existing article on the site, and you handled it correctly by revising our list to keep showing the NRHP name (as it is a list of NRHPs) while wikilinking to the pre-existing article.  And you added the NRHP infobox, keeping the NRHP name there (as it should be).  Further, I edited the article intro to mention the alternative name.  And further, i created a redirect at the NRHP name for the site.  I think we talked about how to do redirects a while back....

It would have been similar if the problem had been we had created a new NRHP article already, before finding the pre-existing one.  Then I would have supported merging our material into the older article, and converting our new article into a redirect to the older one.  That gets to the same result as above.  

In mergers, I do think it is courteous to merge the newer article into the older one, so that the older history of edits stays with the article.  Even if the newer article name is better, because the merged article can be moved with its entire long history to the newer name, after.

Anyhow i think you handled it right.  Thanks for checking in!