I'm in the same boat ... bought a duallie to ride around town etc and saving my other for longer touring. Matter of fact, its a KLX 250S that I freakin love. I found that if you google your question, then go to the "Dualsport" forum and the "ADVRider" forum answers it will help a lot. I wish I'd done that before I bought my MX boots to use on the KLX because I find it hard to shift, and uncomfortable as hell to walk around in if want to check out something cool i see in the boonies. A couple recommended there were an MSR boot [sorry, cant remember the name but it was white and black with a rubber sole similar to hiking boot] and the Alpinestars 2 which is like a mid heigh MX boot with more flexible bottom. The most highly recommended was the Forma Adventure boot that runs 299 via Atomic-moto. At first I thought 299 was alot, but then I read the rational behind spending that and it makes sense. The boot is high quality and will last years and years considering a person could easily drop 100 bucks on jeans or something that might last a couple. One guy said that its better to invest in something worthwhile, than waste money on something else. [ and end up buying the better one second time around anyway] Good luck ... you'll love the KLX
Those Forma Adventure boots look like a great option. You could even wear them on a street bike. Seems like they Are more flexible than a typical mx boot but still good ankle support