I just did one as well. It was GREAT fun! That said, unless you have a desperate dealer trying to unload leftover new bikes or find a truly awesome deal on a used bike, it's unlikely you'll save any appreciable amount of money on a bike as common as a V-Strom.
Our dealers in Sacramento are not very good, so had I decided on a new one I probably could have saved $1000 or so buying in a neighboring state.
A 2004 Wee with (then) 81k miles certainly wasn't anything so special I *had* to fly-and-ride, but the bike was in Seattle where I used to live and wanted to take a vacation anyway. I probably saved $500 or so over a comparable bike in NorCal, but the plane ticket cost $200. Had I slabbed it home, I'd have spent about $60 on gas and $50 on a hotel room. Total savings $190. Not even worth my time. I didn't do it to save money, though.
Besides not having to spend the time to ride up there, added motivating factors were that the bike was set up almost exactly the way I would have done it and that I bought it from the original owner who had gone above and beyond on the maintenance front. I'd personally rather have a bike (or cage) with high mileage and good maintenance than one with low mileage and OK maintenance. Plus, at 12k miles a year you know it never sat for long :thumbup:
I turned the purchase into a week-long vacation, going to Vancouver Island then riding down the coast to Eureka before turning inland to get home.
I did have a backup plan: although I had no reason not to trust the seller, I booked a refundable ticket home just in case.
Registration-wise it varies widely by state. Washington and California (and probably more) plates stay with the vehicle, so it's a piece of cake as long as they're valid. Buy bike, call insurance company, ride home, do paperwork. I even rode mine into Canada without incident.
Insurance should be a non-issue. If you don't have acquisition coverage or if you just want the peace of mind of an insurance card, call the VIN in to your insurance company before you pick it up and you can have an insurance card before you ever touch the bike.
MA doesn't even do temp plates. You can't drive the thing until its registered. And you can't register until its insured.
If you live in Mass, you can use your old vehicle's plate(s) to drive a new one for a week. Technically you have to have gotten rid of the old one first, but that's impossible to prove on the roadside. The RMV even started printing that section of law and an explanation of why Mass vehicles don't have insurance cards on the back of the registration card. Guess too many New York cops were citing Mass drivers for no insurance card :headbang:
This doesn't help if you're buying a bike in Mass. and don't live there, though. In that case you're basically SOL.
I wouldn't leave my plates on a bike I sold. My experience buying a bike in Ohio involved getting a 30 day temporary Ohio registration. When I got the bike back to Illinois, I got permanent registration there along with the title transfer. Check with the state where you are purchasing the vehicle for their regulations.
This is the most common setup--new owner goes to get a temp tag to get home. It's great fun for cages in states that require emissions testing on transfer (two visits to the DMV just to buy a car?!). I used to use my Vermont plates (same rule as Mass) to get cars home even in Colorado. I never got stopped.