For most things a VTXXX compatible terminal would be OK, or a PC terminal emulator. I ran into a few cases where OpenVMS and the HSD05 menus didn't like my Wyse, though. Per Hoff (and he should know), PuTTY works well with VAXen/VMS, and I've heard good things about Tera Term. The included HyperTerm in Windows is pretty bad, though.
One place still makes MMJ connectors, and if you ask around on ClassicCmp or Rescue (sunhelp) you can find someone who makes cables. If not you can take the tab off of a 6-pos modular jack and use that as long as you're careful.