I take Teegy on long walks all the time, he can go for hours. I bring food and water and treats. He lets me know if he needs a wee rest and I carry him for as long as he needs and he lets me know when he wants down again.
My friends have these dog harnesses where you can carry the dog on your chest like a baby carrier if you'd rather do that.
Something like this
Pet Pockets-Front Carrier