and on to Pooley Bridge.
Off to the Lakes in a couple of weeks and going to take my cx bike. Never been up onto High Street from Kentmere. From High Street down to Pooley Bridge was thinking I'd be ok if I run my 'fat' 35mm tyres. I know there a push up on part of the Kentmere side but is the rest doable.
Sounds like purgatory. Soft grassy tracks with 35mm tyres, ooft.
Your 2 options, that I can think of anyway, are up nan bield and then west onto high street, or up garburn and turn off north at the top onto yoke/illbell/mardale Ill bell/thornthwaite and onto high street.
The latter would probably be the best option tbh. There will be quite a bit of pushing, both up and down though. The tops of the hills up there have some rocky descents heading north, but could be avoided to an extent as frostwick and mardale both have wee grassy singletrack routes contouring round them as well as the routes over the top.
It's a nice carry for soft grassy descent.
Almost as above I'd start in Staveley and cycle up round to Borans and then the bottom of Garburn and then up across Mardale I'll Bell to High Street.
If its dry and fine its a cracking place to be up top.
I would do the yoke/ill bell from Garburn option as nobeerinthefridge says,if you look on the map theres some handy singletrack to the Northern (kirkstone pass side) that misses both peaks and stays lower down, much quicker way of getting to Thornthwaite Beacon, be aware after High street and especially this time of year it can be fustratingly boggy in places making progress slow on skinny tyres, descending from the knott, Angle tarn,Boredale hause but heading west towards Hartsop/Brothers water would be my choice on a x bike,Heading back over Kirkstone pass to finish, enjoy.
A slightly longer but more cx-friendly approach is to head west to Dubs reservoir via High Houses, then drop to Limefitt Park and take the Bridleway North, giving you the entire length of the original roman road if you go to the Cockpit by Pooley bridge. Less rocky than the other routes and only carrying will be the grassy pull up onto Thornthwaite Crag.
..An alternative route back is to head East off Loadpot Hill to Bampton, and pick up the (traffic free) concrete road and old A6 (now bridleway)over the Shap summit, eventually getting you back to Longsleddale and Kentmere. Big day out mind!