Ah, funnily enough I was looking at Buckstones on my map the other day and thinking that I hadn't ridden it for a year or two. I find it okay since losing weight but pretty tough when I did it weighing 16+ stone. I have had problems with mad drivers and motorcyclists in both directions though. It is the kind of road that they seem to like to speed on.
I haven't ridden Grains Rd. I come in from the North so I take the B6197 to Dog Hill. Quite hard, with extensive views across Greater Manchester.
Yes, tough climbs from a cold start are not pleasant! I have some pigs round here with gradients to 20+%. I nearly always do battle with the traffic on the A646/A6033 first to warm up
Buckstones downhill is the closest I've ever come to being wiped out at high speed (a car pulling out of Grains Road, ended up in the gutter on the wrong side of the road). It can be terrifying on busy days and best avoided if it's icy (ditto up over Ogden, Huddersfield Rd).
The roads over near you I've ridden quite a lot this year just because of the variety plus lots of cyclists so 'safety in numbers'... that said between Littleborough & Walsden there's a disproportionate number of angry motorists on the wide section of 50mph road adjacent to the canal... must be something in the climate
Early summer I rode the A640 up to Marsden as often as I could... with decent weather & light traffic it's a fantasic, rewarding trundle, brilliant views up at the top!