Cabin, that sounds pretty eerie to me. I had to ditch my own front fork recently, and so I upgraded a little to increase safety. Here's what it cost me:
1. A threadless headset: $20 from your local bike shop.
2. A fork with disc brake drop-outs already welded on them. I went with a $40 set like these: 26" Tripple Tree front Fork
. Cruiser-style bikes like the ones we use for motorized bicycles generally have 1" steerer tubes, which makes it difficult to find good mountainbike forks for them (they use 1.125" steerer tubes).
3. Avid BB5s are a great set of disc brakes - no hydraulic fluid to mess with, and you can usually keep your old hand levers and cables. A set of front brakes can be had for around $30 (here's a place that has them for $27: Avid Ball Bearing 5 Mechanical Disc Brake (BB5) - Wheel World - Culver City and Woodland Hills, California
I installed everything myself, it was easy to do. Total cost was under $100, and I ended up with a much-needed replacement fork and a set of weatherproof front brakes with good modulation and fantastic stopping power.