Mounting A Backpack To Bicycle

How about getting a rear basket and sitting it in that?

A front or rear basket seems like a good idea to me, too. There are many removable front baskets available that, when not in use, can be removed and just leave a clip on the handlebars.

milk crate on back rack came to mind. just a big bucket you can drop the pack into, you know?

When I read the title of this thread I thought you were a hiker who wanted to ride to a trail, and then hike with your pack, and then ride home. I thought this was a great idea...and still do, but of course this isn't your intent.

You've given me an idea though...combining two passions--thanks

Putting it on top of a rack, like a trunk bag could work... just rig up a wider platform (possibly plywood) connected with screws or cable ties, and strap the pack on with a few bungie cords. Although, I do like the idea (and flexibility) of a milk crate too.

This is how I transport a bag:

...& this is how I transport a dog:

A rear basket is a great idea. I think better than just strapping it to the rack with bungy cords because if it sits in a basket, you don't have to worry about the pressure of the bungy cords squishing the contents of your backpack. You can carry quite a lot in a basket or crate if it's secured well to the rack. As long as more than 50% of the weight of the contents is below to top of the basket/crate, you don't have to worry about it falling out. It's a great way to carry food as well, because you won't have to worry about crushing fruits and vegetables if they are just sitting in a basket.

A rear basket or rack like what most people are suggesting is a good idea. It won't get in your way versus a front basket and you could just bungie cord the bag down. Maybe even use the basket for other stuff like fishing equipment? Maybe.