The easiest way is have mDNS advertise the SSH service:

```
sudo cp /usr/share/doc/avahi-daemon/examples/*ssh*.service /etc/avahi/services/
sudo systemctl restart avahi-daemon
```

On the source host you may need to alter /etc/nsswitch.conf to replace `mdns4_minimal` with `mdns_minimal`.

On the source host now say

```
ssh raspberrypi.local
```

(or whatever hostname you chose, followed by .local).

You can set this up on the SD card before the first boot.