Grizedale hause was from Grizedale tarn to patterdale and is easily in the top 10 lakes descents in my view. I've never descended the other side on little tongue above Grasmere. It's utter misery pushing up though and I'd imagine similar going down.
If you want to ride it (the patterdale side) my suggestion would be to start at Wythburn church, head south along the fire road, then over a deer fence along the permissive footpath to raise beck. Carry up raise beck (there's a couple of rocky steps where it helps to have a hand free, so you need to be comfortable carrying the bike or go with someone so you can give each other a hand). Ride round the South side of the tarn then continue down to patterdale. Head to Glenridding and then greenside mines (the youth hostel). Take the bridleway south of Raise to Whiteside bank (steep, much of it is a push for mere mortals) then go to the summit of Helvellyn. Descend via Birk side. This is another top 10 descent though wasn't in the list as it's not a pass. It's fairly difficult in a few places, plus there's a lot of steps which can be quite tiring. Probably easier than wharnscales for example, but perhaps harder than nan bield.
Don't do greenup until you've ridden everything else, especially if you're visiting the area from elsewhere. It's not a complete sandbag, but not far off. Fix the fells started work on the south side a few years ago, haven't been up since so not sure how it's looking these days though. Perhaps that's my plan for the weekend 🤔
Adding wharnscales to rosset-styhead-stake is a serious day out, if that's what you were meaning. Take lights if you try it, you'll probably need them. Don't underestimate the carry up rosset, or the push up stake pass for that matter. They don't look long on a map, but there's a lot of height gain.
