Chet, an alternative system may work with the soils you encountered. Depth to water is the limit factor usually. With Clay a raised bed mound with an application rate of 1/5th of a gallon per square foot per day would be adequeate for your cabin I would think. All rules are different state to state so check with your local health department for their requirements but I wouldn't be afraid to put one in under those situations.

As far as Grey Water goes I would think that the main problem with grey water discharge is the extrememly high amounts of Phosphorus that is in laundry detergent. I would think that this would lead to algae problems etc. You also get small amounts of e-colli from laundry discharge. I have heard of people burying a 500 gallon drywell ( septic tank with holes in the side and no bottom for those who don't know what a drywell is) within 50 feet of a pond that they discharge their grey water to without any harm.

Its not how well you do something,
Its how well you look doing it!