Turton and Entwistle Reservoir is a favourite spot. The top end in particular is stunning. On a quiet morning or evening you could imagine being in the wilds of Scotland.
Until a couple of weeks ago we had only extended the reservoir walk up on to the moors, rather than following the more usual walk which joins up Entwistle with the adjacent Wayho and Jumbles Reservoirs.
Route finding wasn't hard. Although we did have our trusted Viewranger maps on the iPhone they weren't really needed. A decent look at a map beforehand and a few mental notes would see you through.
Entwistle still remains my favourite. Wayho was nice, but a little less wild. If you visit make sure you spend some time (in early summer) admiring the rare wild meadows. Jumbles was also nice, but very very busy.
All in all it was probably 10 miles or so to loop the 3. All easy going.