Urethane bed liner material is a solid paint over replacement for an upgrade easy and with less required time.
Reprinting a trailer can be very expensive and time consuming. Your trailer is like it gets shot with a 12 gauge and #6 shot behind your truck at 50'. It gets all pocked and it requires a lot of sanding to strip, striping the new paint is not easy and most don't have a Bugler striping tool, let alone skill to use it. Then you have new bunks you will want, new lighting, frame harness wiring, lighting that was bad, the list goes on... A good PPG or color automotive style primer, paint and clear coats cost alone about $500 or better. Quotes on repaints and rebuilds generally can run above $2,000 for a quality job.
They have a Great point on the tube frame also. We have seen many invest bucks in a tube frame to have it break and rust internally a year or three down the road. Tube custom frames have come and gone 3-4 times in the last 40 years. "Tex" and Ken Mitchell broke themselves trying to customer service RoadMaster tube frames with channel when they rusted out in the late 1970's and early 1980's. RoadMaster, Mark IV, DriDock, SpringTrail and more all have come and gone due to rusting tube frames. They look cool new but we use our stuff and heat, cool, humidity and continual exterior climates take their toll onthe internal hidden tube areas.
Be sure you check your frame before you start.