My 2 cents
1. Get a good inspection by someone who knows these vehicles. If it's someplace where a forum member can help you then all the better. If there is an Isuzu dealer (ex-dealer) close then get them to do it. I did mine and it cost me about $125. Best peace of mind I ever got for $125.
2. Use a bonded and insured transporter. FedEx has a vehicle shipping department and they are not the cheapest, but they stand behind their stuff.
3. Use a good escrow agent to provide payment once the vehicle arrives and is as represented.
4. Nothing is as good as you looking it over before the purchase, but if that's not an option you're just going to have to be comfortable with this.
Several of the members here have done this and I'm sure they'll chime in soon.
Live, Love, Forgive and Never Give Up