I've done dolly waggon and rangers and I'd say dollywaggon is A LOT harder (in my op of course)
I've also walked up a hevellyn a couple of times and cycled it once. It seems to me the best ascent is (luckily for you) from Glenridding up past the mines and then up the zig zags on Keppel Cove. It's all signposted fairly well and there's only one path to follow. This ascent is nearly all cycleable in the granny of course.
When I did Helvellyn last time I was on a hard tail, so if you've got a full bouncer and you're very competent then Dolly Waggon might be for you. I like a bit of tech but I also enjoy speed so I didn't really enjoy dollywaggon at all, for me there was no reward.
Me n mar mate are going back to do it again in April and this time we're going to go up keppel cover, ride the whole of the ridge as far as we can both ways and then go back down keppel cove, just because it will be insanely fast and fun with little or no tech.
Sticks pass gets a lot of good talk on here. at the cross roads it goes down to Thirlmere so not good if you're parked at Glenridding unless you want to go all the way round the mountain, north or south. If you look at an OS map there is another descent coming off sticks pass and joins the keppel cove path at the mine, I don't know about that route so you might like to investigate.
see my similar thread a few weeks ago (http://singletrackworld.com/forum/topic/getting-onto-and-up-helvellyn-from-the-north-threlkeld)
If you get the weather it is an ace hill.