Hello Velocette 1,
If my experience is anything to go by, the gearbox can be a bit of a challenge, especially if you're used to bikes which change gear when you ask them to and don't take all day about it. My advise is this: change gear in a very slow and deliberate fashion, giving plenty of time for all those robust, whirring pieces of metal to connect with each other. When people say, 'say Saskatchewan' (insert suitable regional variation here) between shifts, they're not kidding. With any luck there won't be too much grinding and gnashing, and you will have at least a few gears to go along with a box full of neutrals. If you can find four gears, you're doing fine.
My bike has the cunning trick of changing up through the gears perfectly, lulling you in to a false sense that all is right with the world, and giving every impression of going back down through them again - except when you go to start off once more, it's either decided upon neutral or third (usually the latter). Never mind - just slip the clutch a bit and let the torque get you moving. Ignore the gravel truck six inches from your back wheel. All the gears are there - but they decide when they'll come out to play.
Wiser, more mechanically knowledgeable folks will no doubt roll their eyes and provide a perfect diagnosis for this ailment, but it's been like that for the last 20,000kms since I got the bike, and probably long before. When I test rode it, I actually started off in fourth, (quite easily too) and had to fiddle back through the gears to approach normality. I suppose I could have identified it as a problem at the time but I just put it down to character.
Even though I know my gearbox is...er, challenging, I have no hesitation about loading the bike up and heading off on lengthy rides. I guess it boils down to identifying what your expectations are. I hear that some people have perfectly normal, trouble free (although still very slow) gearboxes. Mine just isn't one of them. If you expect gear changes like a modern Honda - well, it just isn't going to happen. If you can live with long delays between shifts and perhaps an occasional bit of grinding - earplugs are cheap.
But the bottom line is........all the above notwithstanding, it's still worth it!

Nick