Can use it as a springboard to talk about Imminent Domain and make some references to the Trail of Tears as not all tribes will be so receptive of foreigners trespassing on lands they deem sacred. Work with the NCR or strike out on your own with Yes Man or House and rebuild the path Eastward, acting as a sister mod to TTW and creating a worldspace for the Plains Commonwealth. Then give a questline to take out the Burned Man. Assimilate and break tribes in Eastern Arizona + begin conflict with New Mexican tribes and dabble into BoS territory, retconning everything. Become a Frumentarii and live the life that Ulysses walked before he took another path.