Most of the time it's impossible because even if we can connect from the head node to the compute nodes, we cannot open an X tunnel there. So at the moment what I do is copy the latest file to a filesystem on the head node and then run a lightweight X visualiser on the head node (Rasmol or equivalent is fine there).

We have fancy complicated visualisers and they are great, but I really hope the (often old) barebone ones that work over an SSH tunnel on a flaky VPN keep working for a very long time.