I remember a youtube series from a recent college grad that toured on a Burgman 400. I guess he had the summer off and just rode around the country and visited friends and family. I believe you can tour on anything. You could do a lot on a maxi-scooter with a topbox.
I know my DR650 was probably a little better suited to Highway travel than say an versys 300, but it only had 35HP. It is not like it is what most people think of superslab mile muncher. I still did multiple days over 700 miles on it. It even carried me from Spearfish to home in one long day (over 900 miles). I took that bike everywhere! There were some long highway days that were not fun, but I think that holds true for most motorcycles. The interstate is just a neccessary means to get to where you WANT to go. It carried me on my longest trip yet in 2013 where I was away from home for over 2 weeks and did a lot of camping all over the western half of the country. When I was riding along the coast in California and on the narrow roads in the Sierra mountains, it felt like the perfect bike for those roads. In some cases the smaller bikes are actually better. While in Yosemite, I was able to park and stop at places cars or really big bikes could not. It was crowded but I could always find a place.
I would do a similar journey on a versys 300.
