I have, all of it, 6 days walking. Lovely walk but not a stroll in the park! We saw grown macho men struggling under the weight of too much stuff so you have been double warned!
Friend and I did it all using public transport and the Hadrians Wall bus AD 122.
Train to Carlisle, b&b there, bus to Solway and walk back to Carlisle 15 miles
Day 2 - Carlisle to Walton B & B 11 miles
Day 3 - Walton to Steel Rigg - this was hardest day, lots of wall and crags and up and down, superb views. We stayed at the pub at Twice Brewed for a couple of nights (the youth hostel was occupied by school children and we were not able to stay there) c17 miles
Day 4 - We got the AD122 to Chesters Fort and walked back to Steel Rigg via Housesteads where we had a good look round. 12 miles
Day 5 - Bus back to Chesters Fort/Chollerford then walked on to Heddon. 15 miles. Bus into Newcastle to yha where we stayed for two nights.
Day 6 - Bus to Heddon then walk back, mostly along R Tyne into Newcastle and on to the end at Wallsend, 15 miles.
Train home from Newcastle back to Birmingham.
That was in 2004. The local tourist info centre publishes loads of info and there is a lot on the web and several books about the walk. Most of them go from east to west, starting at Newcastle. I have done a lot of long distance walking and am strongly in favour of going from west to east if that is an option. On the one day we walked "backwards" (day 4) there was a strong westerly wind blowing in our faces which made it a lot harder. One argument I have seen is that by starting in Newcastle you get rid of the built up bit first and out into the countryside for the rest of the time but I thought that part of the walk was really interesting and I enjoyed it more than the stretch from Solway to Carlisle. Because we were able to use the local buses and stay two nights in three places this meant that on some days we did not have to carry everything which was a definite advantage. My only regret about the walk was not having enough time to look properly at the many Roman sites along the way, by the time we got there they were usually closed, one of those days I intend to go back to the area and have a good look round.