Hi Hart,
I apologize that no one has answered you yet, let me try and help you belatedly.
First, when asking questions on G2G like this one that relates to a specific profile, you might attract more answers if you tie the question directly to the profile by adding the profile id, in this case Walker-27340, instead of a more general space like you did here with Walkers of Colonial Virginia. This makes it easier to get to the profile being discussed.
Now in terms of helping, by linking your pedigree up to Joseph Walker, that is already a big help. You've also posted your DNA which is also helpful. To further the research, I highly recommend exporting your DNA from Ancestry to GEDmatch.com and getting a kit number assigned. This permits more advanced DNA analysis to be performed, including comparing your DNA to folks that have tested with other companies like 23andMe asd FamilyTreeDNA. If you need help with the export, just add a comment to this answer and I'll elaborate more.
Another helpful thing would be if you have an online link to the will of Joseph Walker. If you could find that, adding a link from his profile to the will would be very handy. Otherwise, if you could transcribe the key facts of the will and include them in the profile, that would be helpful (e.g., people mentioned as heirs, executors, or witnesses).
Hope that helps!
-William
