how to play an extra large joke on someone

One of my coworkers, L, has a husband, G, who is out on the road a lot. A few months ago, they traded in the pickup they had for a different one that would get better gas mileage for their horse trailer. While they were out shopping, they looked at this one Chevy crew cab that has a TON of enhancements and decorations, etc. Wood trimmed dash, nice interior and exterior package, etc. MSRP around 68,000 - same price as a fairly decent starter home around here. So anyway L has been talking for a few days that she has a friend over at the dealership and wondered if he would let her "test drive" that truck and take it home, stashing her other two vehicles at a friend's house, and pretending that she bought herself a new truck when G came home the next time. We all would laugh at what his reaction would be but no definite plans were made until today. L even called their contact at the bank and got him in on the deal too. He was more than happy to help her play this joke on G. She had to leave early because he was getting home close to the time we were getting off work, and she called us on the road and is going to meet him at a restaurant... in "her" new truck. We are all excited to hear "the rest of the story" tomorrow.