This is what I've done for my Windows JH to access the nested VCF setup deployed via Holodeck. Assuming you deployed the default CIDR (10.1.0.0/20):
Add a route on your Windows JH to point 10.1.0.0/20 to the Holorouter management IP.
Then I added a secondary eth on my Windows JH and assigned it an IP of 10.1.10.220/25 (could be any unused IP in the Untagged-HoL subnet, you can get a list of subnets by running Get-HoloDeckSubnet -Site a | ft -AutoSize in Holorouter when the config is loaded). I also added the subnet's DNS server 10.1.10.129 as the DNS server on that interface in my Windows JH.
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