(I have seen forum posts from owners asking if it ok to run the heating system all night - the answer is yes - it is designed this way! You should experiment with your system in different outside temperatures and you will soon find the settings which work best for you)
You can use the heater in "radiator only" mode - ie with the fan switched off. This is often useful for background heating the van because it uses no battery power at all in this mode. However I have seen some vans where the fan is always forced to be on to prevent over heating - S670 for example.
I have also been asked can you run the fire when driving. The answer is no because airflow down the chimney will blow out the fire. However many owners forget to switch off the fire and drive away ... the fire will blow out and the safety interlock will kick in. At the end of your journey when the van is quiet somebody will say "what's that ticking noise?" - it is the ignition circuit. Many owners have a pre-drive checklist and switching off the fire should be on it!