Normally you return the boat at the base where you rented it. To take it to another base I think is the exception to the rule. You are in full command of the boat, and it is up to you whether you use your days sailing, or stopping and exploring. You are allowed to moor along the canalside almost everywhere, on the towpath side (but several long boats kan be hard to find room for in popular places!) But remember it is never just to "sail along" - there are locks, they are manual, and you operate them yourself.
Remember to check the hiring company's T&C. There ARE age restrictions, as to the skipper needs to be above a certain age. I don't know how that works with more boats hired by a group. But just ask them - the hiring companies we used was very serviceminded. But of course the teenagers are allowed to try their hand at steering.
Here's a link to a map I often use myself. https://www.centralwaterways.co.uk/guides-and-maps/lockmaster-maps/lockmaster-holiday-planner-flat-5th-edition.html
Best of luck with your venture - a great idea!