Some places repeaters might be down due to EMP, ours here in Nye County won't be, they are shielded against it. And they all have solar panels plus wind generators with battery backup in addition to being on AC mains and having propane generators on their sites. We planned ahead.
And we have backup repeaters stored in EMP proof containers, that can be taken to the existing sites or others and set up quickly.
HF, VHF and UHF simplex comms would still work as long as the radios are working. And you can always set up relays to span distances greater than VHF or UHF travel in line of sight.