DriveThruRPG as a free download. Click on this link or the sticker price picture to the left to jump straight to the free HackMaster Basic introductory adventure.
I wrote Danger in Drakesville a couple of years ago as what is called a Learn to Hack adventure. Pretty much a convention demonstration where we help new players roll up their first characters and then run them through a short adventure to let them experience some of the game mechanics.
Danger in Drakesville isn't supposed to be a challenge although there have been quite a few PC deaths. The idea is to let the players naturally flow through the area, suggesting which of their skills might be of use in their adventure. Certain events are presented specifically to teach certain game mechanics, like Feats of Strength, falling damage, skill checks, combat, Poison Saves, etc. The PC deaths I've seen were either from sheer dumb luck (on the bad guy's side) or player stupidity. Don't underestimate a player who doesn't care about their PC. Most PC deaths were due to alcohol poisoning.....
Danger in Drakesville was intended for HackMaster Basic, but it will work perfectly fine for the new "full/advanced" rules that are being printed. The only issues will be that the rule page references are specifically statted for the HMb book, which you can purchase here.