Hi qbcb,
Used to teach guitar/voice at the Old Town School of Folk Music in Chicago. Commuted the 13 mi rt with a small steel string in a Reunion Blues gig bag. It had duel adjustable straps. Sprayed it(heavily) with Scotchguard waterproofing and kept 2 plastic trashbags in the zippered pocket in which I would wrap the guitar then place it in the gig-bag if it rained. Did this for about three years with no warping or damage to the guitar. Though a minor annoyance I never had a real problem with the neck over my head and I used a road bike as my commuter at the time. Had two handlebar mirrors and one on my helmet, too. Would I have it to do over again I would use a mandolin as my teaching tool! There are gig-bags less pricey than Colorado Case or Reunion Blues which will do the job if your guitar isn't an expensive one. My axe at the time(sold it years ago) was a Gurien S2M which is(was...the factory burned down and they aren't made anymore) a fairly high-end small acoustic which justified the fancy gig-bag.