GIV/SP for $5m purchase or an early GV for under $10m would fit all your missions. The 604 and Falcon 2000EX Classic (perhaps add winglets) will do many of the missions but really don't have the fill the seats and fill the tanks range of the GIV/SP. I wouldn't consider the G200 - it will be range limited and the cabin is much smaller than the Falcon or the Gulfstream. Operating cost between the big airplanes is really just the difference in cost of fuel and where you fall in the maintenance cycle. If the Falcon needs a C check or the Gulfstream needs a 72/96 month, there will be big costs. I'm more bullish on the GIV/SP as the engines are cheap to operate ($253 Corporate Care Rate today), crew is readily available, support is robust, and the airplane won't leave you wanting for more range or more room. Sounds like it would fit the budget too. I have a partner in BA, hit me on PM and we can talk further.