Looking for Thomas Naughton/ family

My GGG grandfather was Thomas Naughton who emigrated to the USA around 1845-47 per geneology documents. He was in Montgomery Missouri with one son that was born in 1850 William Thomas Naughton in Montgomery County Missouri. Thomas Naughton had received letters from his father Anthony and mother name is possibly Bridget. A daughter had emigrated before Thomas. The letters come from Westmeath. I recently visited Ireland and did not get to Westmeath as I have never been out of the USA and did not know how to go about researching I dont know how many parishs there are. Im so curious and connected to this part of my family even though they are no longer with me. I lived with my grandmother and great grandfather in Missouri for a time and got my spirit from them. I wish to hopefully pass down the same to my children but, I would also like to tell them a story. I can piece some things together. I have so little knowledge of how our family broke apart and died off over here. I went to one family reunion when I was 15 but, was unable to appreciate that at the time. My dad died early, my grandmother and great grandfather died so I really dont have anyone to ask anymore. I can only guess at the hardships they must have faced. The trail disappears with William Thomas. I cannot find any info about Thomas born about1821 regarding birth, deat, or immigration because there are so many people with that name. I have one census from 1850 where William Thomas was about one year old from Montgomery Missouri. Im sorry I have so much information and not a lot of facts. Any insight would be helpful. Kat Vines-Warr or