I've got experience with this exact setup and can add some useful insight. If your only towing occasionally for short trips, on flat highways, with no passengers/gear in the truck, and don't mind the driving in 3rd gear with the engine screaming, you'll be okay. Personally I don't think you'll be happy for long.
I bought a Starcraft Antigua 195ck 2 years ago when I had an '03 limited V6. It's similar to the Roo but 6" narrower(read less frontal area). It weighs in at 3800lbs loaded to camp but with tanks empty. I lasted 3 short trips with this setup before I had had enough. It wasn't so much the weight, but the frontal surface area of the trailer. I had difficulty holding 55mph on flat highway with the slightest headwind and felt the engine straining. Occasional drops to second gear on hills and no power left to pass.
I have since traded up to an '04 Limited V8. It made a huge difference. With the extra gear (5speed vs 4), load levelling suspension and extra torque I hardly notice the trailer. I tow in 4th (and even 5th on flats with a tailwind)which gives close to the same rpms as the V6 in 3rd, but it sits better in the power curve and is smoother and quieter. Fuel mileage is also better because it's straining less and still has plenty of power to pass. I keep finding myself at 70mph passing everyone :shrug:
In short the V6 will do it but not happily. It's a solid engine that will pull all day but with that weight your pushing the limits. 5000lbs is also calculated with 1 driver and full fuel, any added weight for passengers/cargo must be subtracted from it. You'll definately want a WD hitch with sway control but make sure you have the proper reciever. The stock one on most V6s is bolted to the xmember only and is not certified for use with a WDH.
Let me know if you need any more info and happy camping :cheers: