Another alternative I use is that I put my clean clothes in 2 gallon zip lock (store brand)  freezer style bags.  My spouse found a bunch of them as good as the name brand but at 60% of the cost.  I squeeze the air out of the clothes, for this takes up a lot less space.  Then, the foregoing is packed in a heavy mill plastic trash bag.  The trash compactor bags are a good idea, likely thicker, but I always thought they were limited size.

While at Cabela's, I noticed a huge ziplock bag, 3 feet long or so, and wondered if this would be a good purchase.  I may get one to try it out on my Sept. trip.