On demand mounting is fast and reliable:
karl@erlangen:~> time cd /home_karl_6700k/
real 0m0,355s
user 0m0,000s
sys 0m0,000s
karl@erlangen:/home_karl_6700k>
karl@erlangen:~> journalctl -b -u home_karl_6700k.automount -u home_karl_6700k.mount
Nov 20 19:51:21 erlangen systemd[1]: Set up automount home_karl_6700k.automount.
Nov 21 20:44:54 erlangen systemd[1]: home_karl_6700k.automount: Got automount request for /home_karl_6700k, triggered by 7290 (bash)
Nov 21 20:44:54 erlangen systemd[1]: Mounting /home_karl_6700k...
Nov 21 20:44:54 erlangen systemd[1]: Mounted /home_karl_6700k.
Nov 21 20:48:42 erlangen systemd[1]: Unmounting /home_karl_6700k...
Nov 21 20:48:42 erlangen systemd[1]: home_karl_6700k.mount: Deactivated successfully.
Nov 21 20:48:42 erlangen systemd[1]: Unmounted /home_karl_6700k.
karl@erlangen:~>