Hi Peter,
I think charcoal is the right way to go in your case. I recommend you make charcoal in a TLUD (Top Lit Up Draft). This is a relatively low temperature method of making charcoal that removes just enough of the volatiles so that you don’t have to worry about tar. It also yields more charcoal and is safer than kiln type processes.
Rindert
Here is a very simple gasifier I made from a pipe. This type of gasifier is very forgiving. One thing to remember is that there must be at least 24 inches of charcoal above the air inlet nozzle. LINK