We stayed at the Hilton in September and it is about a 20 minute walk from the hotel entrance to the turnstiles. We walk pretty fast as well so assumed it would be shorter (the hotel told us it was 20 minutes), but nope, pretty much exactly that! It wasn't an issue for us, but I could see how it would be for some.
You can also take the ART shuttle, which charges a each-way per person fee. We always walked and never took it, but the hotel recommended it. As ImDMous said, you can also walk across the street to the Toy Story lot and take the shuttle from there, which a lot of people do, I think.