Now you know I'm never one to rain on anyones parade but.....

A few random comments:

I wouldn't go for this. If I want to go anywhere I have my own outfit and would use that. I think the target market is for want a better description (and excuse the labels) "holidaymakers" rather than "adventurers". Edit to add: I think the sidecarists you'd get would be from say the US who didn't want to bring their own rigs over. I think you'd get a lot of solo riders who fancied a go.

I think you are spot on thinking about the training aspects of taking Dave-the-Weekend-Harley-Rider and plonking him on a Ural. I think you need to add to this how you'll deal with blokes who own Fireblades at home wringing your Urals to death at 70 mph (is there something like the AA?) and how you'll tell old boys who've pottered about on their own bikes for years that they are not fit to be let loose on your bike. Maybe talk to the local Harley shop? Will they rent solos to the point and squirt riders who can't get their head round three wheels?

I think a big draw could be winter riding. Maybe find a forrest trail where you can use the Urals abilities and lead the trip to include some nice winter camping, open fire etc? You have more control than handing over they keys.

Good luck with whatever you try.

Andy