Ok, now that I see the pic, I'd call that a "landscaper's trailer"! That changes everything!
2x6's will work, just remember to use some heavy duty angle brackets so your hardware goes through the grain, as end grain is very weak, and have your top rails overlap the uprights to keep water out of the end grain.
I'd also install some cargo rings on either side down low near the rails for straps. By mounting them low, you add the friction of your stake sides to the equation, so if your straps get wet and stretch, there is still front- to- back resistance. If you can get sufficient angle on your straps, blocks should not be necessary, but only time will tell.
Most of the wind will be from passing vehicles, as the trailer is in the car's slipstream, so side to side stability is crucial, a line from the bow back to the trailer should be enough to hold against sudden braking.
The biggest problem I see will be the bounce. Take the trailer for a ride down a bumpy dirt road and see how it handles. I suspect that It'll bounce all over the place with an unloaded suspension. There are two cures, the first is pricey, the second is hard on gas. You can take it to a trailer shop and have them pull a leaf (you need a pro to know which is the right one and to repack them) and downgrade the weight rating, or add sandbags to get it to "working load" (usually about 1/3 the tare weight), but it'll suck gas!
2x6's will work, just remember to use some heavy duty angle brackets so your hardware goes through the grain, as end grain is very weak, and have your top rails overlap the uprights to keep water out of the end grain.
I'd also install some cargo rings on either side down low near the rails for straps. By mounting them low, you add the friction of your stake sides to the equation, so if your straps get wet and stretch, there is still front- to- back resistance. If you can get sufficient angle on your straps, blocks should not be necessary, but only time will tell.
Most of the wind will be from passing vehicles, as the trailer is in the car's slipstream, so side to side stability is crucial, a line from the bow back to the trailer should be enough to hold against sudden braking.
The biggest problem I see will be the bounce. Take the trailer for a ride down a bumpy dirt road and see how it handles. I suspect that It'll bounce all over the place with an unloaded suspension. There are two cures, the first is pricey, the second is hard on gas. You can take it to a trailer shop and have them pull a leaf (you need a pro to know which is the right one and to repack them) and downgrade the weight rating, or add sandbags to get it to "working load" (usually about 1/3 the tare weight), but it'll suck gas!
