Shelties are great dogs, but they don't meet the "relatively furless" requirement mentioned earlier. Otherwise they would be a great suggestion.
Honestly, no dog is without some coat maintenance. Don't let that be too big of a deterrence. Short haired dogs have other issues that require attention to deal with.
Dogs can get sunburned if they have really short coats, or very fine lighter coats. I knew someone who had a yellow lab that they had to put sunscreen on if they kept him outside for more than an hour or two. A rare case for a lab, but I've heard stories from the vet about other dogs being sunburnt as well.
Springer spaniels are wonderful dogs as well. They are a hunting dog so taking them on hikes would not be an issue at all. They stay within the 30-40 pound range typically as well.
I've dealt mainly with large hunting dogs most of my life. Labs and golden retrievers mostly. My family has owned many different types of dogs over the years. Mostly large breed hunting dogs, some collies, farm dog mutts, springer spaniels, and beagles. Boxers too, but I think they are butt ugly with a lot of personality.
Beagles are great dogs if you can live with their barking and howling. I can't though.
As far as coat maintenance for a sheltie goes, I find that they require the same amount of effort as a typical golden retriever does. Less dog, more fur, but no more difficult to maintain.
Coat maintenance on a springer spaniel is basically the same as a sheltie too because they have such fine fur it gets crap caught in it easily. They also seem to need more bathing because they secrete an oil that makes them swim better. Not as bad as a lab, but more like a golden retriever in that respect.
My biggest suggestion to you is to find a reputable breeder. Many of the breeds mentioned are overbred and can have many health issues. It took me quite some time to find a sheltie breeder who did health testing, and had a blue merle pup for sale. Shelties are known to have a plethora of vision problems and hip issues. Mine has no such issues because of proper breeding, and he was tested for all of the common health problems with documentation before I purchased him.
I'll have another 8-10 years with my 3 year old sheltie now that should be relatively health problem free. He's a happy and healthy dog, and I don't have to deal with some of the pain and expense that many others have had to endure. I've known many people to buy the "cheap" puppy of many different breeds that had so many health issues. They love their pets, and their pets love them, but they paid dearly in the long run. Avoiding those problems, and supporting a good breeder is worth a higher initial cost always.