Thats good then, Just a few tips for you...
1-Be careful going under bridges, they can have very limited visibility and low roofs. Also the surface may change from gravel to cobbles that can be interesting when wet. Best to get off and push.
2-Keep an eye on your mileage. Its very easy to go a considerable distance, just remember you have to do it all again to get back home!
3-Keep an ear open for faster cyclist, it can be a shock when someone comes belting passed.
4-Keep an eye on the time too, it seems that going one way on the towpath during daylight hours can be very nice, but at dusk and after they attract some "interesting" charicters that might like to have a go on your bike.
5-Make sure you have enough water and food. Especially if your route takes you through unfamilier teritorry. You might be 20 meters from a shop but never know it. I have a cable lock that I keep wound around my seatpost so I can lock it up for some very quick shop stops.
6-Use googlemaps to check out your local canals, and spot routes or curcuits.
7-If you are in the Midlands have a look at this site for route ideas...
https://sites.google.com/site/westmidscycle/