Enthusiast

Let's say that a cyclist wants to go touring for the first time. As they do their planning, a lot of the logistics will be based on what sort of pace they ride right? (Note: When I say pace, I'm including actual cycling pace, average time riding per day, and frequency of rest days. Basically how far on average a cyclist will have gone over a certain number of days.) How can a cyclist who hasn't toured estimate this? What factors about the style of tour they intend, their current fitness, etc. can they look at to aid in their planning. I'm especially interested in how current fitness can translate into pace, daily mileage, and required rest days. This has personal relevance but I want to keep the discussion generalized.