I much prefer trainers to walking Boots for long walks. Unless you're doing some serious slopes trainers are better I think. Certainly more comfortable when on the Downs.
Yeah, regularly do. Whether it be South Downs, London Canals, Lake District etc. Myself and a mate do regular walking weekends and can easily do 20-25 miles in a day. As long as you take it at a steady pace and have food and water it's fine. Will do these walks on my own sometimes but much more...