The issue is NOT the surface, but which route to take. After I took the above picture I found an article in the local paper discussing the same topic, in that one someone suggested using the old Southern Cambria Railway instead. The Southern Cambria Railway went on the opposite mountain side of this valley. The problem with it is that as the old railway right of way nears Conemaugh Borough, it disappears (I believe it was filled over when Pa 271 was built over it).
If you look at my picture looking across the valley you will see PA 271 climbing up the hillside. The Southern Cambria Railway was and is below that Roadbed. You can barely make it out in some of the pictures. Using it instead of expanding on the Stable Bend Tunnel side, has promises. Right now the bike trail to to go from Johnstown to Mineral point via the Staple Bend tunnel, and then cross UNDER the railroad and over the little Conemaugh River. At that point the trail goes on the Southern Cambria Right of way to South Fork, re-cross the Little Cinema River on a public Bridge and follow PA 53 to Cresson and Altoona. The trail between Mineral point and South Fork is already completed (And PA 53 follows the old Portage Railway). Now the Southern Cambria Railway is a relatively flat trail (The Southern Cambria being an 1905 built Interurban trolley line is NOT as flat as the Trail AFTER the Stable Bend Tunnel, but it flat when compared to most routes in this area). Thus the Southern Cambria route is NOT as flat as the Staple Bend Tunnel trail, nor PA 53 from South Fork to Incline #2 (the second incline on the old Pennsylvania Canal).
The problem is NOT uphill from South Fork, that is almost already done, PA 53 is NOT that busy a road and is flat till Incline #2 (Which is steep and long, but then flat again). The Railway between Inclines #2 and Incline #3 is almost still in use as a flat public Road. PA 53 then goes gradually up to Cresson, where you can catch the New Trail being build between Incline #6 and 10 (of which I will post later). Thus no serious problem exists on the line EXCEPT for the Johnstown to Mineral Point section. Once done you can bike from Johnstown to Altoona at a very gradual rate of climb. Thus we keep coming back to this breach in the line of the path and how to solve it. The other issues are minor in comparison.
For more on the Southern Cambria, here is my post last year on the Southern Cambria. I have newer pictures but I have NOT added them to my photobucket account to put on the net, so the following cite is from 2006-2007:
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=324x1488