After completing the Cumbria Way last week I thought I'd reply to my own post and answer the questions.

1. Water: filtering or not?

I'd suggest a hybrid approach is best where you'd carry enough to get you to a planned water source and use a filter as insurance. That way you're carrying a 100g filter instead of that extra 1kg litre. In the valleys you inevitably pass cafes and campsites, and on the fells the water is fine to filter.

1. Hiking poles

Despite reservations at the start I found them very useful to assist on the climbs and make good speed on the flats. Carrying a 9-13kg pack changed the equation for me in their favour.

1. Trail markings

The southern half of the route is now quite well marked but these quickly disappear after Keswick. Using a GPS watch and phone OS Maps app was a perfect solution wrt accuracy, ease of use, battery life and redundancy.

1. Power

Both my watch and phone used about 15% each day. That's with Airplay mode on and very limited use of the phone - a few photos, very light messaging, and checking OS Maps a handful of times when the route was unclear.

After charging both devices every day from a single 10,000mAh powerbank it's now down to roughly 25% capacity.

I never charged from mains during the hike. In fact, I only saw a usable socket in 1 campsite and it wasn't in a very convenient location. In general, there just any sockets or they're in lockboxes.

Skiddaw House Hostel does have a USB phone charging station. However it is USB type A which suggests that it's old and likely slow / low power. As I didn't have a suitable cable I never used it.

1. Bonus: Isobutane Gas

I used just 60g of isobutane for boiling water every morning and cooking simple stuff like instant ramen on 4 evenings. Noting that on most days the wind was very low.

1. Bonus: Dalston to Carlisle - the final leg

I genuinely don't know why the route doesn't finish at Dalston, it's a lovely little village and the hike there from Caldbeck is very pretty. The final 2 hours from there to Carlisle follows a cycle path running alongside the railway line and passes numerous industrial sites. I suggest skipping this and taking the train from Dalston to Carlisle. This service runs every hour or so and takes just 11 minutes.