Nothing beats full fenders
After experimenting with homemade fenders, modified throwaway fenders from a bike shop, I broke down and spent $40 of my Christmas money on some real 35mm zefal road bike fenders.
Man, what a difference they make. It rained last night and I just road 20 miles on wet, often muddy roads. After the ride, I was still spotless and my bike was clean save for the lowest most parts.
BTW, you CAN get full fenders onto a Trek 1000 or any other road bike with reasonable clearances. The back fender goes on fine, but the front took some time with a rotary tool. If anyone knows a good, fast, easy way to cut or file the sides that would be good. Basically, you need to narrow the fender where it goes under the fork. I also had to break off the little metal thing that goes around the brake bolt and use a zip tie instead.