I was thinking you could also take the same route through the UA, but rather than turn left onto 4th ave., you could continue on University across the bike crossing to Stone Ave. and then turn left onto Main/Granada and then continue south to Cushing St.
Here is a link to the proposed route:
http://www.gmap-pedometer.com/?r=3439018 Is there a pedestrian crossing at Treat and Speedway? Otherwise you could continue on Pima to UMC and then cross under Speedway using one of the tunnels at the UA and then hit University blvd from there.