Traveler’s HOT L Volume 2 has a solid time travel mechanism (complete with a full description) and short stories of its application and consequences when things go wrong. It’s brilliantly written too!
Patterns on Pages: Secrets of the Sequenced Symbols is a beautifully written full length novel following in the HOT L series by CR Downing with time travel integrated throughout.
CR Downing (Chuck) has a brilliant time travel mechanism in “The Traveler’s HOT L” where personal time lines are described as threads which are woven together to form a fabric of time. In this interview Chuck gives us more insights into his reasoning.