Corny kegs $17.99
... Unfortunately I'm not to knowledgeable of Hoff Stevens kegs other then some reading on the site...
1. As long as you take apart the tap and sankey and clean/sanitize them well, you should be good. Make sure your regulator holds pressures well when you first hook it up.
2. If you can, I'd do a good soak in PBW/OxyClean, and then sanitize in Starsan (my sanitizer of choice anyway).
3. PBW/OxyClean.. I don't think you can get in there and scrub pretty well, but a good hot soak should do the trick.