I can help a little.
Griswold, perhaps the most collectible cast iron, was made until the 1950s. The good stuff dates back to the 1930s, and the name on their stuff was Erie, not Griswold, up the the early 1900s. They were located in Erie, PA.
The other make that I collect is Favorite Piqua Ware. The company went out of business during the Great Depression, 1933 I believe, so their skillets are at least 80 years old. Their skillets are finely cast and quite light in weight. They were located in Piqua, OH.
Between Griswold and Piqua Ware I must have at least 60 skillets. And then there are all the Dutch ovens, griddles, etc. It can get quite obsessive!
If you post some pics, I'll see if I can identify what you have.
I believe your Dutch oven was made by Lodge. Typically, they didn't put their name on it. The pattern on the underside of the lid (for self basting) looks like Lodge. The different manufacturers all had their own self basting patterns.