According to this site http://www.gmap-pedometer.com/ it looks to be just under 1 mile (.9131 miles) walking west along Katella and North on Harbor. I've never stayed at the Hotel so I can't speak to what it is like.
I don't see it on the ART route, but it looks like there is a stop fairly close by for the Candlewood Suites if the walk is a bit much.