The 61C takes that route. Try google transit directions.
Allegheny county airport WON'T take one-way car drop-off
Enterprise misled me. Allegheny County Airport's Enterprise location will not accept a one-way car rental drop off from Washington, DC. However, their Homestead Enterprise location will, at 908 East 8th Avenue. I used Google Maps with the bicycle route feature turned on to plot a route from the Homestead Enterprise office address to McKeesport, so I can get to the GAP trailhead to begin my ride. Would somebody kindly check this map link and tell me if this is an OK bikeable route? Thanks! http://tinyurl.com/8nj8jfd
Just jump on the GAP at the waterfront.
use this link to zoom in and you can see where the trail is/starts in the waterfront. Also, we rode the loop on both sides of the yough that day so you can see how either side will take you to boston trail head. hope this helps...
http://connect.garmin.com/activity/157548154
You're making it way harder than it actually is, try this. Turn on the bicycling layer in Google Maps and you will see the Steel Valley Trail which leads to the GAP.
google bicycle directions from there aren't that great. take the steel valley trail! it requires turning left onto the east waterfront drive bridge to pick it up http://goo.gl/maps/Pkd3C
Homestead -> McKeesport is actually a much nicer ride than from the airport.
Basically, Homestead is on the GAP.
@ moto - you just got a gift. There is a new trail connection, opened just this year, that connects the Waterfront, the large commercial development in Homestead, to the GAP trailhead in McKeesport (or very close to it).
I like to err on the side of caution, others might call me crazy on this one, but I'd recommend heading WEST from the Enterprise Office (left as you leave their building) and taking a right on Amity Street to enter the Waterfront Complex. After you cross the railroad tracks, take your first right, which is the service delivery road for the businesses.
Follow this until it curves behind Lowes, and crosses the main access road into the complex. The trail will be 10 feet beyond that road. You will take the trail to the RIGHT.
You can access the trail by heading RIGHT from the Enterprise Office, then turning left onto Waterfront Access Road (a flyover over the railroad) and grabbing the trail at the bottom of the overpass ramp, again heading to the right on the trail. (per dmtroyer's routing)
(Once on the trail, the river should be on your left in Homestead...)
I don't recommend this routing, although it is a mile or so shorter, because I think the stretch of Route 837 (aka Eigth Avenue) between say Ravine Street and the Rankin Bridge is a little iffy on a bike. And getting across 837 to the access road to the mall, puts you in the middle of vehicular traffic more intent on navigating their way to the Rankin Bridge.
Here's the trail map: http://www.steelvalleytrail.org/trail.htm
You'll be getting on just east of Milepost 4, where the line becomes solid red again.
+1 what Swalfoort said: Amity Street, RR tracks, first right to go behind the businesses, Lowes, turn right on the trail.
And if you're looking for food before you return the car, I'm a real fan of a Mexican place called Smoke Barbeque Taqueria, 225 East 8th Avenue Homestead, PA 15120, (412) 205-3039. Remarkable tacos and supposedly the best mac-n-cheese in Pgh.
I thought Enterprise's big thing was "Enterprise will pick you up". Check to see, but I believe you can go to them to turn in the car and then have them drive you to the trailhead.
+1 for Swalfoort's suggestion. We use that routing with our tandem, coming from the Nine Mile Run trail over the Homestead Grey's Bridge. Behind the stores there is little traffic and a lot of room.
Motorapido - have your map handy when you get to Mckeesport, the trail ends before Lylse Blvd. and the signage is weak. You need to go out to Lylse and make a right, lots of road construction here. Go through 2 or 3 lights, but do not cross the bridge, you need to bear right under the bridge to continue on to connect to the GAP. I ride through Mckeesport on my commute, but I have never connected to the GAP that way.