While the fork is a definite area to be weight conscious of, you can save a TON of weight in your wheel and tire choice. Depending on how much you can "finesse" your way around singletrack, etc...a light weight set of wheels and tires can save you as much as two pounds. Pretty much everything else stock on that bike is rather heavy, the crank/bottom bracket for sure, and the lower end mechanical brakes are most likely weight pigs. I have no idea about the frame weight of that bike, it's aluminum and that's about as much info as I could find. You could certainly continue to upgrade parts and eventually end up with a pretty light bike then upgrade the frame later on, if you want. Considering I did my first mountain bike race in 1989 on a bone stock Rockhopper, I think you will do ok with a 28lbs bike, your going for fun and experience here I would think. Of course, I know lot's of people with super light bikes that never race....just like nice light bikes is all...and there's nothing wrong with that!! Good luck to you, and remember....above all, just have a crapload of fun!
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Droping the hamer since '86