Folks,
I got these directions from a kind and smart soul and wanted some feedback:
1. The Amtrak station is on the corner of Liberty/Grant.
2. Follow grant 5 blocks until you hit 1st ave.
3. Take the "eliza furnace trail" or jail trail as it is known to the bridge across the river. This is the hot metal bridge.
4. Take the other side trail until the end, keep going when it appears to end. This will put you into a parking lot. The road it is on is 837.
5. Follow ths about 10 more miles to the Mckeesport bridge.
6. Cross it.
7. Make a left on 148 (i think?) and then cross the bridge into Boston, Pa.
8. The only weird part about my directions are the end of the trail. You are literally riding next to railroad tracks along rocks, but it is only 200 meters and I have done it on a carbon road bike with 23mm tires before.
9. The trail really starts under the bridge in boston.
I made a map on bikely. Look at it closely on satellite mode I made sure to follow the way I would go. This ride is not for the faint of heart. It is unfortunate that there is no easy way to get from downtown to the Boston trail head.
http://www.bikely.com/maps/bike-path/324528
Potential tricky points.
-at the end of the southside trail walk about 1/10th a mile next to the railroad tracks
-then go through sandcastles parking lot you should be ok since it is open for the summer.
-837 is high traffic / high speed. Proceed with caution
It is a confusing 10 or 15 miles but after that it is smooth riding to dc.
nevermind, while I was reading this thread there was something on Ch. 2 that I hoped was about finishing the trail... but no dice 
837 does NOT sound like a fun way to get there...
