Look at the performance chart from Cessna, it shows Max Payload for the Citation 560 Ultra ++ at about 2,350 lbs, not your required 2,500 lbs. With this payload you can carry the max payload about 1180 nms in nil wind conditions. The distance from PDX-DAL is 1493 nms which today happens to be 1280 nms with a 75 kt tailwind (Jetplan data). That gives you about a 2000 lb payload. So how are you getting 2500 lbs?
No alternate? No reserve? What?
Mutt