Originally Posted by Russ Roth

Actually looking at the components groups Alivio should be mid-range, there are tourney, altus, and acera below it and above is Deore, LX, XT and XTR, if you consider 3 below and 3 above then Alivio and Deore are your mid-range lines in MTB and is a fairly reliable and under appreciated group. If you want nicer still a quick shop of universal cycles produces
KMC X10 chain
XT m786 rear der
HG81 SLX 10sp cassette 11-36
M6000 right shifter
total 144.00 plus a 100.00 wheel would be less then 250 for a nice upgrade that should work with the crank. If I was bored and searched enough sites and ebay I'm betting I could trim that down another 20.00 and 10speed would be an easy fit on there.

OP; getting it down to 25lb will not be easy, cassettes are lighter than freewheels but cassette hubs are heavier then FW hubs, you'll save some weight with the parts like I listed but not a lot. The frame, fork, seatpost and stem really account for a lot of weight you can do nothing about and those aren't light parts. The fenders, rack and kickstand don't help. Your crank is heavy but for this style bike it is a nice design and a better BB like a UN55 might only save 1/4lb from my experience, you have to go a lot more expensive to save some weight there. You'll be another 200+ in the hole to switch to a lighter crank with chainguard that saves you anything and at that point it does start to get pricy.