Hi camper -
I did the full thing back in 1985, but did a couple of (shorter) stages through the Lakes - Rosthwaite to Grasmere and Grasmere to Patterdale - last summer with a couple of friends. I’m 70 plus (they were much younger) and found those stages pretty tough going in advanced age, but not impossible - you just have to take your time and go at your own pace. The Yorkshire Dales ‘roll’ more but are still not to be underestimated, while the first couple of days following the edge of the North Yorkshire Moors escarpment can feel back-breaking as it’s an ‘up, down, up, down, switch back. So there’s tough bits in each section. Weather should be OK in June, but don’t quote me as it is impossible to predict - it’ll be about as good as it’s going to get then and the daylight hours will be long. So you should have plenty of time to complete each stage.
If you are like me, it’s the descents that hurt most these days and I wouldn’t attempt it without my trusty walking poles. Come to that, pretty much wouldn’t attempt any hike without them nowadays.
You have the main suspects in your list of companies but you might check out Mickledore who do much the same stuff. There are others, but I have no experience of any of them. I’m doing the Cleveland Way next May (God willing, following wind and all that) and we are using Brigantes, who have been super easy to deal with at the booking stage at least, so maybe another company to compare and contrast.
If it’s the challenge of the C2C that calls to you, fine, but there are other perhaps less strenuous trails to go at in the U.K. - let me know if you want any suggestions in that regard. The aforementioned Cleveland Way for instance, but it’s not a stroll in the park, given that it runs concurrently with the C2C round the N Y Moors escarpment section and the coast is no pancake either.
Hope you get something sorted out to your satisfaction.
Ian