Near the Cherry Gardens/ hospital in Wigan.
Ill probably go up to Standish, then up the hill at red rock and over the canal to Haigh Hall, through Blackrod and up to Rivington.
Ah, right, I've found the Cherry Gardens on the map. If you head up to the roundabout at the bottom of Red Rock and carry on up there you can come up to Frederick's Ice Cream shop near Adlington. From there you can get to Chorley or back towards Rivington.
Here's a
30 mile loop for you. There's some good climbs in there. The section between 8 and 10 miles will get a bit ropey if it's wet or there's lots of leaves down, and I wouldn't attempt it if there's ice. The climb up to 12 miles is quite tough in parts (for me, anyway!), then there's some fairly fast descents which again are quite ropey if it's wet and definitely not to be trifled with if it's icy. The descent from 18-20 miles is good and straight and fast. There's a good cafe at about 21 miles, then a bit of climbing at 25 miles then a fast descent back down Red Rock Hill.
This is a bit longer than you asked for, but not by much, so maybe it's some you use to you. This is a
53 mile loop with some fairly long climbs, and you can add in some very steep ones too if you fancy it. You start out going up Red Rock, over to Blackrod then into Horwich, up Chorley Old Road, which is a cat 4 climb. If you want a brutal diversion at this point you can drop down Mill Lane, up Foxholes Road and Marklands Road, and then back across George's Lane to the top of Chorley Old Road. Drop down and take the Bolton Ring Road round past Moss Bank Park to Bradshaw. Bradshaw Road is another long steady cat 4. In Ramsbottom there's another long climb on Lumb Carr Road, or you can head down into Ramsbottom town centre and then head up Carr Street, Tanner Street, Rawson's Rake and Chapel Street - this is the infamous Rake, which has a 25% section near the end. From the top of there, head up through Helmshore to Grane Road, another long cat 4 climb. Drop down towards Blackburn and then come back up Roman Road, which is another long steady one, I think a cat 4. From there you head to Edgworth and Chapeltown - there's a Strava segment round there called the Edgworth Rollercoaster and the name is accurate. Cut back towards Belmont through the woods and then you'll come to the back end of Rivington. It's a cat 4 to the top of there and then a good long descent which is definitely not to be remotely considered if there's ice on the ground. Watch the cattle grid near the bottom, and then you're heading back towards the cafe from the earlier ride if you need a brew at this point. Over the reservoir, under the motorway, then up Dark Lane takes you back towards Haigh Hall, and then you can head back the way you originally started out and go back down Red Rock.
Both these routes are reasonably quiet in terms of traffic. Obviously there's more closer to civilisation, particularly around Horwich and Bolton, but there's nothing too problematic, and no particularly unpleasant junctions in there.
There's plenty more I could suggest to you if you want. Some more tough climbs, too
