There are a few members on this Forum that use a macerator pump and dump through a hose into their home's sewer system. That may alleviate some worry about arriving home with tank contents.
You don't need to have digestion going on in your holding tank. Having plenty of water to help dissolve solids and the agitation when on the road will break down sewage faster than any bacterial method.
Adding soap or a surfactant to the holding tank helps to get everything more slippery. I use cheap laundry products, occasionally. Cheap softener tends to have more perfume added, a nice byproduct of buying inexpensive water softener.