Originally Posted by
Tourist in MSN
I did not expect to see a grocery store for at least a week and a half when I took the photo, and at that point had not seen one for six days, so this segment of this trip might be the heaviest I ever packed
A backpack is great for overflow capacity for a day or so with small loads and smaller amounts of baggage. I wouldn't use one or even consider it in the situation you are talking about here. I might carry a tiny one for side hikes though (with your load you wouldn't notice the 2.5 ounces of the sea 2 summit one). The advantages of wearing a backpack wouldn't really apply for your trip. You wouldn't be going into stores so taking your theft worthy items with you isn't a big deal. You'd need a much bigger backpack carrying more volume and weight than I'd want to ride with to make much difference with a load that size. The weight wouldn't be going down much in a day.
At this point in my life I don't think I will ever be willing to carry food and water in large amounts. I either figure out ways to do caches or skip that trip. I will probably miss out on some great trips, but there are plenty of others that meet my criteria. I might be a bit more likely to bend my rules on that for dirt/off road bike touring than for backpacking, but the older I get the less likely I am to want to be a pack mule.
Of course water is a far bigger problem than food since food can be as low as 2 pounds per day (more likely a bit more, but still) while water is going to be at least 8.4 pounds per day. For me weight is the concern. Adding volume may be inconvenient, but it isn't that big of a deal compared to carrying a lot of extra weight.