Complex sentence: There are a variety of different types of wilderness therapy programs, with the most common models being sustained expedition or base camp models with a typical stay of 8--12 weeks, other single expedition style models involve single 25-35 day trips.
Split into simpler sentences: There are a variety of different types of wilderness therapy programs. The most common models are sustained expedition or base camp models with a typical stay of 8--12 weeks, while other single expedition-style models involve single 25-35 day trips.