Disk brake rotors require disk specific hubs.
You can mount a rear caliper with a frame adapter like "A2Z" on EBay. I used one on my diamondback. Using disk brakes on the rear will require you to get a special rear sprocket that will work with a disk rotor installed.
You can buy a front fork with disk brake tabs for the caliper. You can drill some rigid and springer forks to post mount a caliper, like "Venice Boy" did.
You can see that it can be expensive. It might be cheaper and easier to just get a drum brake wheel for the front. Cheers
yes disc brakes are WAY better then traditional still brakes like u-brake,v-brake,linner ect.I never tried the hydraulic disc brakes,mine are the mechanical type,I've heard that the hydraulic type are a pain in the a$$ to fix if your out on a bike ride and they fail on you.My disc brake will stop me on a dime,in dry or wet weather.They havent failed me yet.If you decied to go with disc brakes try to buy Avid Calipers alittle pricey but well worth it.There fully adjustable,some of the cheaper calipers you can only adjust 1 of the caliper pads,in turn makes the pads rub......hope this helps a little.....Randy
Just a side note pdub,on the disc brake bracket,depending on your forks you might need to grind down the keyway on the disc brake bracket,I had to on mine,I used a drimel took about 2 minutes.The bracket works great..Randy.. oh yeah with your Avid caliper you'll be stopping on a dime.