"The 34th U.S.C.T. served in Florida and South Carolina until disbanded on Feb. 28, 1866. The regiment came no closer to Kentucky than Hilton Head SC.
Dozens of women named April Lewis have lived in Kentucky or adjoining states. Unless you can date that inscription, it could have been made in 1798 or 1998."
Your original inquiry did indicate that the regiment probably wasn't in the area. Based on your request for any information and God's blessing in advance, I confirmed your statement about this. I also searched dozens of family trees on the internet including anyone named April Lewis. The next sentence, "Dozens of women named April Lewis have lived in Kentucky or adjoining states," is a summary of that research project.
The final sentence in my reply, "Unless you can date that inscription, it could have been made in 1798 or 1998," is my best opinion on your inquiry. You said you already knew this. Maybe so, but words along these lines weren't in your post. Nor do I find April Lewis mentioned as "LT April Lewis."
If everything I wrote confirms or repeats what you already know, and we both agree about available facts, how can you construct an insult out of that? I also agree that it would be wonderful if someone could offer something substantial to help identify this person, but since so many people have carried that name over time, it's going to be tough to do.