I can see the 1923 border crossing, and that says that Mr. Sheppard was the name of the relative/friend in the country from whence Alexander came (Canada). On the 2nd page, there is the information about the address you mentioned that he was going to, but it doesn't say anything in the column where they asked if he was in the US before, so that would indicate it was the first time he came to the US.
I see a 1907 passenger list to Quebec for the Virginian for an A.E. Littlejohn, but there's not a lot of detail to determine if he's your guy. He's listed as a 30 year old single miner going to Montreal. Under nation or country of birth, he has a ditto under a bunch of guys listed as born in Sweden, so that may or may not be correct.
I did post other records above, including the city directory entry & the Social Security application. Considering the date of birth on the Social Security application matches your guy's, it's almost certainly the right one.
If you wanted to spend money on it, you could try to order a Michigan death record, as explained here -
https://www.michigan.gov/mdhhs/0,5885,7-339-71551_4645---,00.html You could also order his original Social Security application for a fee. It would give his address & employer at the time of his application. More information available here -
https://www.legalgenealogist.com/2020/11/16/ordering-the-ss-5-2020-style/The 1950 census is expected to be released next year, so that may be helpful. As time goes on, more of the Michigan death index may be released. So even if the information isn't readily available now, it may be in the future.
