No trap in these toilets.  So good chemicals are required to contain any odor, especially in hot weather.  Most places we camp do not have full hook ups.  Out of about 130 nights in the past 3 years, i don't think more than 10 nights were we somewhere with sewer.  We do some camping with no hookups but our favorite campground is Lost Mine outside of Bryson City, North Carolina, near the Nantahala River.  All it has is electric outlets nailed to trees and a few sites with water.  We average 3 trips a year, with stays of about 7-8 days.  The year of the Olympics, we spent 16 nights there.
http://home.midsouth.rr.com/theadams...y/nantahal.htm