A very simple AWS Neptune terraform plan

This terraform plan will create a new vpc and two subnets, each in a different avilability zone.
In addition it will create a bastion through which you can tunnel to the vpc endpoint where the cluster presents it's service.

The outputs from the terraform template will give you a suggestion for how to do the port forwarding so it should be a case of just copy and paste and you'll have local access to your cluster endpoints.

It's worth noting that this can take at least 10 mins to complete the creations of resources.