Yes it is only possible to access custom tours through the http://www.streetvisit.com interface.
Even though I've spent time developing this it would be great if Google did finally allow custom virtual tours to be displayed in Street View.
Who knows perhaps Bing will or Apple when their mapping product comes out.
Yes getting users to switch from Google maps itself is and will be difficult but through added content in the form of custom tours, if we can get enough of them to make things interesting, I hope it will work.
Also want to add lots more functionality perhaps making it switchable between Bing maps, where applicable, and Apple's when their product is released.
There's loads of things I want to eventually add in functionality wise like social elements plugging into Facebooks API perhaps EBAY most definitely Twitter.
With geolocation information systems GIS and augmented reality being the new buzz words it really does have potential.
Recently I applied to be a Google approved Photographer for Google Business Photos. Had a really interesting conversation with my contact there. For those not yet aware Google is providing a facility to businesses to have their own tours available in Google Places. I asked my contact if these listings were eventually going to be included in StreetView. But they are not now and he said he didn't know when they would be.
Not only does Streetvisit provide this functionality now it also does it in a way that is scalable and available to existing tours of many different types whether from krpano users or others. KRpano though I think has the most flexibility and also compatibility as well as functionality.
With the latest release including video player plugin supported on multi platforms as well as the huge range of additional functionality that Krpano provides having an interface that supports this as opposed to just the custom tour tiles option that Google provide as the main way to add custom content has to be the way forward.
My goal now is to open this up to the KRpano community as a free service. So anyone out there that wants to start adding tours let me know.